She came out strong with "Girl on Fire" and "Try Sleeping With a Broken Heart" before performing her new song "Show Me Love" for the very first time, with an eager audience learning the melody beforehand so they could sing along loudly. Keys tucked a familiar anthem into the new song, singing a bit of Post Malone's "Congratulations" in the middle.

Alicia Keys made the most of her six-song set at iHeartRadio Music Festival on Saturday night (Sept. 21), with a mix of new songs, classics, covers and special guests that made an instant impact.

Her next surprise came when she started singing a bit of her 2007 hit "No One" before playing the piano strains of "Someone You Loved" and inviting its singer/songwriter, Lewis Capaldi, onstage to sing with her. The song made for a beautiful duet, and when Capaldi left the stage, Keys hollered, "That's my jam!"

She wrapped up the set with her "Part II" version of "Empire State of Mind," strategically changing some of the New York-specific lyrics at the end to "let's hear it for Vegas!"

Day 2 of the iHeartRadio Music Festival continues with Mumford & Sons, Chance the Rapper and Marshmello with Kane Brown. Find out how to watch the concert live here.