Continuity mistake: When Ali leaves the club with Marcus the first time she is wearing a grey dress with a large keyhole opening in the back. When she gets back to Jack's apartment the next morning she is wearing a grey dress with no keyhole in back. Instead the grey dress has a straight-across back with spaghetti straps. Oops! Wardrobe goof.
In the scene where Christina Aguilera tries to audition, the song she plays just before Cher stops her is 'Nasty Naughty Boy' from her Back to Basics album.