Will Forte Sings the MacGruber Theme Song 4.52K Whitney Jefferson 05/21/10 11:51AM Filed to: Late Night Late Night Will Forte Jimmy Fallon TV Video Snl macgruber "This isn't your father's SNL movie," advises Forte while his Mother watches in Jimmy Fallon's audience. He continues, "It's an R-Rated movie... a hard R" and then treats us to a rapid-fire swearing storm. I laughed my entire way through.Don't forget, MacGruber is out today!