The show, set to air Saturday, has also booked 14-time Olympic gold medalist swimmer Michael Phelps as guest host and rapper Lil Wayne as musical guest.

"SNL" creator-producer Lorne Michaels told Politico Obama might cancel if Hurricane Ike causes much damage in Texas.

"If it's serious, it will change everything for us," Michaels said. "The tone of the show will shift, and it would be inappropriate for the senator to do if it looks in any way like it's going to be a tragedy."

"SNL" also planned to have former cast member and head writer Tina Fey on Saturday's show, playing Republican vice presidential nominee Sarah Palin, but her participation was unconfirmed Friday, Politico said.

Obama appeared on the long-running, Emmy-winning comedy series last year, when he was running for the nomination against New York Sen. Hillary Clinton and a field that also included his running mate, Delaware Sen. Joe Biden.

If Obama appears on Saturday's show, Michaels said he's hoping the Democratic presidential nominee will appear in more than one segment "but that will depend how things go in dress (rehearsal) and whether (he is) comfortable with (the material.)"

"The things he's hopefully going to do are morphing daily -- it's comedy, it's not a platform speech."