This isn't the first time Gaga has been a surprise guest at Newman's show. In September she performed a trio of covers with the musician, who is an old friend of the pop star.
This time around she sang versions of "Orange Colored Sky," a song made famous by Nat King Cole, and the George Gershwin standard "Someone to Watch Over Me." Watch a clip of the Gershwin cover below.
So Lady Gaga Crashed the Plaza Hotel's Oak Room Last Night [Sound of the City/Village Voice]