The Twilight Saga: Eclipse' won best male and best female performances for lead stars - and real life couple - Robert Pattinson and Kristen Stewart, while the pair also won the Best Kiss prize at the event at the Universal Studios' Gibson Amphitheatre.
Picking up her Golden Popcorn, Kristen poked fun at Oscar-winning actress Natalie Portman, who was also up for the award, saying: "Sorry, but the popcorn is mine."
British actress Chloe Moretz won two awards for Best Breakout Star and Biggest Badass Star while the 'Harry Potter' series missed out on all the big prizes, with only Tom Felton winning his category for Best Villain in 'Harry Potter and the Deathly Hallows Part 1'.
For more news and photos visit Kristen Stewart or Robert Pattinson's profile pages
Robert Pattinson and Taylor Lautner kiss as Kristen Stewart and RPattz win MTV Movie Awards ‘Best Kiss’ gong - VIDEOS
He joked: "This will look very nice in my downstairs toilet."
Robert Pattinson made sure to embarrass his 'Water for Elephants' co-star Reese Witherspoon, with whom he previously appeared as her son in 2004 movie 'Vanity Fair', adding the pair had "f**ked" on their latest film.
He joked: "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**k you."
British star Robert continued to joke at her expense, adding he had learnt lessons from their time together.
He said: "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 per cent lesbian."
However she did not let him get away with it, and upon accepting the Generation Award from the cast of 'Twilight', she turned to Robert and said: "You're the best motherf**ker in Hollywood!"
It was not the only shock of the night - Justin Timberlake groped 'Friends with Benefits' co-star Mila Kunis' breasts while the presented the award for Best Male Performance.
Justin said: "Even though we're in the movie 'Friends with Benefits', we've never dated."
Then, grabbing her chest, he added: "We have a totally platonic relationship, which is why I can do this."
Full list of winners at the 2011 MTV Movie Awards:
Best Female Performance: Kristen Stewart 'The Twilight Saga: Eclipse'
Best Male Performance: Robert Pattinson 'The Twilight Sage: Eclipse'
Best Movie: 'The Twilight Saga: Eclipse'
Best Kiss: Kristen Stewart and Robert Pattinson
Best Villain: Tom Felton 'Harry Potter'
Best Jaw Dropping Moment: Justin Bieber 'Never Say Never'
Biggest Badass Star: Chloe Moretz
Best Scared as S**t Performance: Ellen Page 'Inception'
Best Line from a Movie: Alexys Nicole Sanchez 'Grown Ups'
Best Breakout Star: Chloe Moretz 'Kick Ass'
Best Comedic Performance: Emma Stone 'Easy A'
Generation Award: Reese Witherspoon