Letterman acquiesced, calling Oprah with a phony voice and pretending to be "Lindsay Lohan's secretary." The 66-year-old late-night host quickly dropped the charade, getting a laugh out of Oprah, who quipped, "Very good, Dave! The David Letterman who's retiring?"
The conversation quickly turned to Lohan, as Oprah (whom Lohan has called her "mentor") gave her take on how Lohan is doing now.
"I think she's doing really okay," Winfrey, 60, said. "I think to have cameras following you around for every phase of your life, and you are trying to pull your life together, I think that's a really difficult thing, so we're really pleased she's making some progress," Winfrey added, bringing Lohan to tears.