By DAILY MAIL REPORTER
F-bomb! No one was expecting the foul-mouthed and F-word laden exchange between Reese Witherspoon and Robert Pattinson at the MTV Movie Awards in Los Angeles last night
Reese Witherspoon and Robert Pattinson both drop the F-bomb on live TV
Reese makes a dig at Blake Lively's alleged nude snaps
Co-stars Justin Timberlake and Mila Kunis grope each other onstage
Robert Pattinson and Taylor Lautner lock lips
The Twilight Saga: Eclipse scoop five popcorn awards
The MTV Movie Awards is known for its crude jokes and risqué behaviour.
But no one was expecting the foul-mouthed, F-word laden exchange between Reese Witherspoon and Robert Pattinson at the star-studded event in Los Angeles last night.
Reese, 35, who was honoured for the Generation Award, was introduced by her co-star and friends, Patrick Dempsey, Chelsea Handler and 25-year-old Robert.
Crude: Reese shocked the crowd when she told Robert that he was the 'best motherf****r in Hollywood'
And the the trio's toasts to the actress went from sincere to crude in a matter of moments.
It all started when the Twilight star began his speech.
He recalled that Reese played his mother in the very first film he appeared in, 2004 British costume drama, Vanity Fair.
He said that he blamed the Oscar-winning actress for some of his scenes being cut from the film.
Flashing forward seven years, he then referred to their most recent film, Water For Elephants.
'Seven years later we worked together on a movie called Water For Elephants and you played my mother...I didn't cut you out, but I did f*** you,' he exclaimed.
Dropping the bomb: It came after R-Patz joked how Reese had played his mother in the 2004 film Vanity Fair and how he went on to play her lover in their new film Water For Elephants
Jaws to the floor: Reese was left open mouthed as she watched on from the audience, as was straight-laced Harry Potter star Emma Watson
Cuts to the crowd showed shocked audience members, including 21-year-old Emma Watson, whose jaw was practically on the floor.
The gag was made live on American television, although the show was airing on a slight delay, enabling producers enough time to scramble to the bleep button.
Robert then proceeded to embarrass the Walk The Line actress even further.
He said that he had learned lessons from Reese during the time that he knew her.
'Now I know that Southern girls can wear girdles but they can't talk about it, Tequila is like Lays chips, you can't just have one, and that it is possible to be 33 percent lesbian,' he said.
And the banter didn't stop there.
Advice: During her acceptance speech, the Hollywood actress also addressed the industry's younger actresses, to offer her advice
Turning the air blue: Reese Witherspoon accepts the MTV generation award as, from left, Patrick Dempsey, Robert Pattinson, and Chelsea Handler look on
Taking it all in stride, a good-natured Reese took to the stage and addressed the adoring crowd and her presenters.
'Oh my god. That's crazy, First I have the three most ridiculous people on earth giving me this award,' she said.
And then after a long pause she informed Robert that he had missed the punchline with his joke.
Touchy feely: Justin Timberlake and Mila Kunis also shocked the audience when they groped each other's private parts onstage
'You're the best motherf***** in Hollywood,' she suggested was a better way of telling the gag, referring to how she had played his mother and lover.
During her acceptance speech, the Hollywood actress also addressed the industry's younger actresses, to offer her advice.
'It's also possible to make it in Hollywood without a reality show,' she said.
And in a surprising almost direct dig at Gossip Girl's Blake Lively, she said: 'And if you take naked pictures of yourself with your cell phone, you hide your face.'
Hands on: Justin grabbed onto Mila's breasts in a move that once again drew gasps and laughs from the audience
What Reese was referring to is the controversial pictures that surfaced online last week, purportedly showing the actress posing naked in a series of self-portraits,
Blake has since said that the risqué snaps are '100 per cent fake'.
It wasn't just Reese and Robert getting crude at last night's awards.
Justin Timberlake and Mila Kunis also shocked the audience when they groped each other's private parts onstage.
Stoked: Robert was thrilled to snare the Best Male Performance award
The co-stars who starred together in the film, Friends With Benefits, made the obscene gestures as they presented the first award of the night for Best Male Performance.
'Even though we're in the movie Friends With Benefits, we've never dated,' Justin said.
To which Mila added: 'We're like brother and sister.'
Presenters: Blake Lively and Ryan Reynolds had a ball as they presented the Best Kiss award to Robert Pattinson and Kristen Stewart
It was then when Justin grabbed Mila's breasts in a move that once again drew gasps and laughs from the audience.
'We have a totally platonic relationship, which is why I can do this,' he said.
Mila then grabbed Justin's crotch, replying ,'which is why I can do this.'
Sealed with a kiss: Nicki congratulates winner Kristen Stewart from the movie series Twilight as Ashton looks on with glee
And then just before announcing the winner as Robert Pattinson, Justin said: 'and the winner is...I think we just found out! What a shameless reference to my penis!'
Their tongue-in-cheek antics stem from reports back in March suggesting that Justin's break up with then-girlfriend Jessica Biel was due to his affections for Mila.
Tricksters: After winning the Best Kiss Award, Kristen and Robert pretended go in for a kiss
Male love: But instead he ran into the audience and laid one on co-star Taylor Lautner
Celebration: Robert Pattinson, Kristen Stewart, Taylor Lautner and members of the cast of The Twilight Saga: Eclipse accept the award for Best Movie
They were also reportedly spotted at a party looking very cosy.
The two then joined forces to present an award at this year's Oscars and to some observers their 'giggling chemistry' was all too apparent.
And they gushed about each other on the red carpet, with Justin telling E! Online's Marc Malkin that shooting sex scenes with Mila wasn't a hard thing to do.
Onstage beauties: Katie Cassidy, Leighton Meester, and Selena Gomez introduced American rapper Lupe Fiasco to the stage
Stunning: Emma Watson looked gorgeous as she debuted of the new Harry Potter clip
Boo, hiss: Actors Emma Stone and Ryan Goslinglook on as Tom Felton accepts his Golden Popcorn award for Best Villain handed to him for his role as Draco Malfoy in Harry Potter
Justin said: 'That's an easy thing to do. I think I could speak for all the men in the world when I say that's the easy part.'
Since shooting wrapped on the film at the end of last year, both Mila and Justin ended long term relationships, sparking rumours of a romance between the two.
Mila had been dating Home Alone star Macaulay Culkin for eight years until the beginning of January, while Justin announced his split from actress Jessica Biel after five years together.
Surprise! Justin Bieber surprised fans and fellow celebrities alike when he showed up on stage to accept his award for Best Jaw Dropping Moment
At the time, a source close to Mila claimed she had nothing to do with the split between Jessica and Justin.
'Mila had nothing to do with their break-up', the source said. 'In fact, no one came between them.'
'They decided their relationship ran its course and it was time to move on', the insider told People magazine.
Happy: The teen scored the award for his role in Never Say Never - he was sporting a new look with brand new ear piercings in both lobes
And the source added: 'They're not in a relationship. They star in a movie called Friends With Benefits but they're just friends. That's it. They are not together'.
The shocking star behaviour didn't stop there at last night's controversial ceremony.
A very jovial Robert Pattinson, who appeared to be having a ball with his comedic antics, also surprised the crowd with a very steamy kiss.
Pranks: Presenters Ryan Gosling slapped Steve Carrell as Easy A actress looked on as the trio presented an award
But it wasn't his girlfriend and co-star Kristen Stewart on the receiving end.
Robert and Kristen tricked the crowd when they went onstage to collect the Best Kiss award for the third time for the Twilight series.
After Kristen acted coy with Robert, he said: 'You don't want to kiss me don't you?' I just think there is someone in the audience that will appreciate it even more.'
Adorable: Cameron Diaz had the honour of awarding seven-year-old Alexys Nycole Sanchez who won the Best Line From A Movie Award
Packed to the rafters: Host Jason Sudeikis stands on stage as he does a monologue to open the 2011 MTV Movie Awards in Los Angeles
Then to which Kristen replied: 'Go get him honey, go get him! '
Running into the crowd, Robert ran straight up to co-star Taylor Lautner and laid a big kiss on his lips, much to the crowd's screaming delight.
Justin Bieber also surprised fans by showing up unexpectedly to collect the Best Jaw Dropping Moment Award.
Hilarious: Jason Sudeikis, the show's host, starred in his own version of The Hangover in which Eva Mendes makes an hilarious cameo in
The 17-year-old was reportedly supposed to a no show at the event, when he took to the stage to be awarded by Danny McBride, Nick Swardson and Aziz Ansari.
Earlier his girlfriend Selena Gomez nearly let the cat out of the bag when she walked the red-carpet solo, and was asked by numerous reporters 'if her boyfriend was attending', to which she first replied 'yes' before quickly saying 'no!'
Other highlights of the night was Emma Watson debuting the never-seen-before new clip for Harry Potter and the Deathly Hallows - Part 2, which is due to be released in July this year.
Gag-laden: In the clip she gets a tattoo on her face and also bites off Taylor Lautner's finger
The English actress was all smiles as she stepped on stage in her cream mini-dress with embellished collar and sleeves.
Jason Sudeikis, the show's host kicked off the fun filled ceremony by starring in his own version of The Hangover, in which he went in search of Taylor Lautner after being astray by one of the film's original stars, Justin Bartha.
Eva Mendes also makes a hilarious cameo in the clip in which she gets a tattoo on her face and bites off Lautner's finger.
On the night, The Twilight Saga: Eclipse was the big winner, scooping a whopping five golden popcorn statuettes.
Justin Timberlake grabbed Mila for breast, and she for him
Kristen Stewart and Robert Pattinson Win Best Kiss- MTV Movie Awards 2011