Duff amused by Eminem's rap about her buttocks

Teen singer Hilary Duff is thrilled after learning Eminem rapped about her bottom in his single Ass Like That.

The soon-to-retire rapper praises the buttocks of a host of female stars, including Jessica Simpson, Gwen Stefani and Mary-Kate and Ashley Olsen on the track.

And of Duff's he raps: "Hilary Duff is not quite old enough / So I ain't never seen a butt like that / Maybe next year I'll say ass and she'll make my pee pee go doing, doing, doing."

When 17-year-old Duff learned of Eminem's cheeky lyrics during a guest appearance on MTV show Total Request Live, she blushed, before responding: "I never knew the exact words to that, but it's funny."