The British hunk told the audience at the Gibson Amphitheatre in Los Angeles he was embarrassed because he didn't think he'd win the coveted award over Jesse Eisenberg, Daniel Radcliffe, Zac Efron and Twilight co-star Taylor Lautner.
He said, "Thanks very much. I'm consistently surprised."
Justin Timberlake had the MTV Movie Awards audience laughing as he presented the Best Male Performance prize with Friends With Benefits co-star Mila Kunis on Sunday night (05Jun11) - by cupping her breasts.
The stars poked fun at reports they are dating - like their characters in the film.
Timberlake said, "Mila and I have never dated... Totally platonic relationship, which is why I can do this," placing his hands on her breasts.
The straight-faced actress responded by saying, "And it's why I can do this..." before grabbing Timberlake's crotch.
And the laughter didn't stop there - as Kunis said, "And the winner for Best Male Performance is..." Timberlake joked, "I think we just found that out," adding, "What a shameless reference to my penis."