Colbert sings James Taylor's parts.

By Jessica Goodman
November 25, 2015 at 01:03 PM EST

Carly Simon’s had a busy month: She released a memoir, called Boys In The Trees, on Tuesday, and also a new double-disc collection, Songs From The Trees (A Musical Memoir). As part of the promo tour for the projects, Simon stopped by The Late Show With Stephen Colbert on Tuesday night.

Colbert spoke to Simon about her career, and asked her if they could duet on “Mockingbird,” the Inez and Charlie Foxx original that she and ex-husband James Taylor covered in 1973. The track was the lead single off Simon’s 1974 album Hotcakes, and she and Taylor performed it together for years.

Simon obliged and Colbert took over Taylor’s vocal parts: