The group visited the Baby hitmaker during a studio session on Tuesday, with Horan taking to Twitter.com to tell fans all about the trip a day later.
He posted: "In the studio with our boy Justin Bieber last night, it's gona (sic) sound great!"
The tweet prompted fans and music sites to report the What Makes You Beautiful singers were working on a song for Bieber's upcoming album Believe, but the American teen idol's spokesperson is adamant the speculation is not true.
The rep tells GossipCop.com: "They just came by the studio and heard some of the album Believe."
Suggested For You
SUBSCRIBE AND FOLLOW
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements.Learn more