Watch B.o.B Sing Jessie J's 'Price Tag' Chorus at Billboard's WinterFest 

Check Out Our Full Music Coverage From the Sundance Film Festival!

B.o.B performs at Billboard\'s Winterfest at Park City Live on Thursday, Jan. 22, 2015 in Park City, Utah.

When B.o.B performed "Price Tag" at Billboard\'s Winterfest in Park City, Utah, on Thursday night, he had a fun surprise for fans, singing a bit of Jessie J\'s chorus as well as his rap.

"If you consider yourself a real music fan, I feel like you know what the f--k is about to happen right now," B.o.B declared before launching into the hit. The Sundance crowd seemed to love it -- check out the full performance below. 

Sweet Talker Jessie J, Ariana Grande & Nicki Minaj

Digital Songs Jan 31, 2015 24 Bang Bang Sweet Talker Jessie J, Ariana Grande & Nicki Minaj

Streaming Songs Jan 31, 2015 24 Bang Bang Sweet Talker Jessie J, Ariana Grande & Nicki Minaj

On-Demand Songs Jan 31, 2015 26 Bang Bang Sweet Talker Jessie J, Ariana Grande & Nicki Minaj

Billboard Canadian Hot 100 Jan 31, 2015 15 Bang Bang Sweet Talker Jessie J, Ariana Grande & Nicki Minaj

Hot R&B/Hip-Hop Songs Jan 31, 2015 26 Not For Long Not For Long B.o.B Featuring Trey Songz

R&B/Hip-Hop Airplay Jan 31, 2015 16 Not For Long Not For Long B.o.B Featuring Trey Songz

Hot Rap Songs Jan 31, 2015 19 Not For Long Not For Long B.o.B Featuring Trey Songz

Rhythmic Songs Jan 31, 2015 19 Not For Long Not For Long B.o.B Featuring Trey Songz

Kurt Cobain Doc, Iggy Azalea & Scott Weiland Top Music Events

Iggy Talks Haters, Career Longevity & Taking Inspiration From Madonna

Next Gen at Sundance Party Announced by Hollywood Reporter, HFPA