The Dirty Projects/Roots musical love affair continued today (Nov. 25) on the set of "Late Night With Jimmy Fallon," as two members of the Brooklyn-based group joined the Roots to back Mos Def and Talib Kweli on their song "History."

The show airs tonight on NBC; the studio version of the track can be found on Mos Def's latest Downtown Records album, "The Ecstatic."

Vocalists Amber Coffman and Haley Dekle were on hand for the performance, which came three days after the Roots' Questlove, Kirk Douglas and Owen Biddle made a surprise appearance with Dirty Projectors at New York's Bowery Ballroom. The two groups hit it off after Dirty Projectors performed in late September on "Fallon," where the Roots are the house band, and are talking about collaborating again in the future.

Dirty Projectors will close out a busy 2009 with three shows in Brazil, beginning Saturday in Goiania. February gigs at New York's Jazz at Lincoln Center (19) and Los Angeles' Walt Disney Concert Hall (27) are also on tap and will likely feature brand new music as well as special guests.