Sarah Silverman, one of Conan O'Brien's earliest Late Night guests, returns as one of Conan's final guests

Silverman was only 22 and in the midst of her one and only season on SNL when she appeared on Late Night with Conan O'Brien on Nov. 3, 1993, two months after the show's launch. "Thank you for being such a big part of our foolishness for the last 28 years," Conan said Tuesday as they reminisced about her first appearance. Silverman and fellow SNL alum Kevin Nealon, who also appeared on Late Night in November 1993 and who visits Conan on Wednesday, are the only guests from Conan's early months as a late-night talk show host who are scheduled to return for his final batch of episodes in late-night. There will, however, be a mystery guest on the Tuesday of his final week who could potentially be a guest from his first-ever show, which included John Goodman and Drew Barrymore.