Will Forte Sings Curse-Filled 'MacGruber' Theme (VIDEO)

Want to know the difference between 'MacGruber' and other 'Saturday Night Live' movies? Well, according to star Will Forte, it's the fact that 'MacGruber' is an R-rated movie.

That's a "hard R." Yep, that means strong language and sexual content.

On 'Late Night With Jimmy Fallon' (weeknights, 12:35AM on NBC), Forte sang a very curse-laden version of the 'MacGruber' theme song. At the end he apologizes to his mom for dropping so many f-bombs. If it weren't for The Roots, we'd want an apology for our ears too.