The Irish star gave a charming performance with the UK singer.
Niall Horan and Anne-Marie gave the live performance debut of their new single 'Our Song' on US TV last night.
Joined by a classic sports car in studio, in line with the music video for the song, the pair belted out a powerful and emotional performance of their new single.
Released a couple of weeks ago, 'Our Song' is currently number 9 on the Irish singles chart, having debuted at number 10.
Speaking about the new release with RTÉ's 2FM recently, the pair admitted that they wrote and recorded the song in under two hours. When asked it if was the quickest song he's written, Niall said: "I’ve written songs in like 10 minutes but that's because I knew exactly what I wanted to say.
"We were very lucky though that Anne-Marie had that concept, it was very relatable."
Anne-Marie's concept for the song revolves around the ending of a relationship, and how a song you once associated with that person can make you wish you'd never heard it.
Here is the full performance from 'The Tonight Show starring Jimmy Fallon'. 'Our Song' is out now.
Previous to 'Our Song', Niall Horan's latest release came in 2020 with his album 'Heartbreak Weather'. The album went to number one in both the Irish and UK album charts.