The pop star was also tasked with singing Harry Styles' "Adore You" as a soca song and T-Pain's "Booty Wurk" as a soft pop ballad.
Trainor was excited to sing a soca version of "Adore You" as she grew up listening to and performing soca music with her Trinidadian uncle.
Fallon meanwhile performed Will Smith's "Gettin' Jiggy Wit It" as a 1950's rock n' roll song and Tones and I's "Dance Monkey" as Frank Sinatra. The late night host had the screen turn black and white for audiences at home during the performance.
Trainor, while sitting down with Fallon for an interview, detailed how her and her family was in a soca band together named Island Fusion. Fallon then presented old footage of a young Trainor and her family performing onstage.
Trainor recently released her third studio album Treat Myself which includes the singles "No Excuses," "Wave" and "Nice to Meet Ya."