The man known as Dr. Phil, who has been dispensing advice in a column in "O" magazine, visited Winfrey Friday in New York, where she was marking the 10th anniversary of her magazine.
"For the first time in over 40 years -- and I have two kids and they've never seen me without a mustache -- I am going to take off my mustache," McGraw told the audience at Radio City Music Hall before lathering up, the New York Daily News reported Saturday.
McGraw said he felt "awful drafty." after exposing his upper lip.
The New York taping kicked off a weekend of celebratory festivities, including self-help seminars and a sneak preview of Winfrey's cable network at the Jacob Javitis Center Saturday, the New York Post said. Winfrey also scheduled a one-woman show and a "Live Your Best Life Walk."
Fans waited for hours in lines that wrapped around Radio City, awaiting a chance to participate in the "Oprah" experience, the Post said.
Nick Dillihay, a 19-year-old New York student, told the Post he won tickets through a contest and brought his mom to Friday's taping as an early Mother's Day present.
He said he expected "to be hypnotized by Oprah's legendary aura."