Jennifer Aniston was on Conan last night (again, talking prosthetic penises, though her chat with friend Chelsea Handler was more lively) and her appearance on The Ellen DeGeneres Show airs today. Watch a preview clip below. Aniston admits she feels guilty for helping to set up boyfriend-costar Justin Theroux so he’d have to breakdance on his first Ellen appearance. (Aniston sent over his special breakdancing shoes.) She also plays a prank on a bike salesman, which is worth watching if only for the moments line-feeding Ellen leaves her hanging and the guy says he wishes he could hit on her.