One of those people is Tonight Show host Jimmy Fallon, who decided to not simply invite her to duet with him, but to explore the history of duets, a la his "History of Rap" collaborations with Justin Timberlake.

Within five minutes, the two traded lines through Sonny & Cher's "I Got You Babe," "Mockingbird" (popularized by James Taylor and Carly Simon), Kenny Rogers and Dolly Parton's "Islands in the Stream," the Human League's "Don't You Want Me Baby" (allowing Fallon to show off his faux-Brit accent), Stevie Nicks and Tom Petty's "Stop Draggin' My Heart Around," and Elton John and Kiki Dee's "Don't Go Breaking My Heart."