Gaga did 20 minutes on the Simpsons fine, and she did 40 minutes on Lady Gaga meets the Muppets (christmas?) special which did have a lot of singing, oh but her Saturday Night Live was excellent... She had this one skit where she played a 90 year old lady with cats shut-in has-been version of herself trying to convince the UPS delivery boy (Kenan Thompson) that once upon a time she was famous, so he should make out with her, but he didn't beleive her, until he saw a picture on the wall of Laddy Gaga with President Beyonce. Gaga looked and sounded like Fran Dresher's Grandmother from the Nanny.
She'll do fine.