Winfrey, who last appeared on Letterman's chat show 16 years ago, recently agreed to return to the popular late-night programme, two years after the comedian began lobbying for another visit.
And to prove to the world that her mystifying feud with Letterman has come to an end, Winfrey is working hard to look her best for the 1 December (05) appearance.
She says of her Thanksgiving plans, "I'm having some friends over and that's it. I get that smoked turkey from Tyler, Texas, that's already done, and I'll do some light veggie thing.
"I can't be eating potatoes, honey. I've got to go on David Letterman and I can't have a belly for that."