Zedd, Echosmith & All the Surprise Guest Appearances at Billboard Hot 100 Fest 2017

Kevin Mazur/Getty Images for Billboard Magazine
Zedd performs during Day One of 2017 Billboard Hot 100 Festival at Northwell Health at Jones Beach Theater on Aug. 19, 2017 in Wantagh City.

Out at Long Island, N.Y., for the third annual Billboard Hot 100 Fest, pop, hip-hop, and dance stars were out in full force. With a star-studded lineup on hand, there were naturally plenty of opportunities for collaboration.

Here is a recap of our favorite surprise guest performances from the weekend of Aug. 19-20.

Zedd Brings Out One of the Cool Kids
During his after-dark DJ set on the main stage Saturday night (Aug. 19), the recent Billboard cover star welcomed Echosmith singer Sydney Sierota. Together, they launched into Echosmith's 2013 hit "Cool Kids," with the gifted vocalist singing her famous part.

Ryan Rocks With Blackbear
Opening up the Sun Stage Saturday, pop singer Phoebe Ryan recreated her recent single "Forgetting All About You," released on Columbia earlier this month. Complimenting Ryan's green hair with his own pink-dyed crew cut, Blackbear came on stage and sang his guest verse from the IDGAF, get-over-your-breakup anthem.

Fat Joe Is Major Key
During the second half of DJ Khaled's main stage set, Fat Joe's presence reigned supreme. Observant fans could feel it coming; Joe entered the area in grandiose fashion, being driven towards the stage with his full entourage minutes after Khaled's made its arrival. When he got onstage, Fat Joe performed "All the Way Up," "What's Love Got to Do With It," "Lean Back," "Make It Rain," and his new single, "So Excited."

Lil Yachty Brings Out A$AP Ferg
The teen hero welcomed the Harlem rapper and made the collab count, rocking alongside him for a sizable portion of his Sun Stage set. They performed "New Level" and "Work" together; then Ferg stayed out to do "Minnesota" with Yachty, even though he's not even on the studio version.

We’ll update this story as more surprise appearances happen this weekend!

Billboard Hot 100 Fest 2017