Lewis Capaldi joined his good friend Niall Horan on stage at the 103.5 Kiss FM Jingle Ball in Chicago (December 18, 2019), delivering a duet of Katy Perry’s “Teenage Dream” that surprised the crowd.

The pair exchanged laughs and playfully warned each other about nerves before launching into the cover. Capaldi strummed his guitar softly while Horan’s voice floated, and together they pulled off a version that reminded everyone why the song still feels fresh — ten years on.

Fans and critics alike have called the moment underrated — it wasn’t part of the setlist mash-ups people expected, but the spontaneity made it special. Their chemistry on stage, built from a clear friendship and mutual respect, turned the unexpected into one of the night’s most memorable highlights.

Capaldi and Horan’s bond has been visible off-stage too; interviews and social media have shown them as pals who challenge each other and bring out the best in one another. That “Teenage Dream” duet at the Allstate Arena reminded everyone: when two vocalists with heart jump in together, magic happens.