The Grammy-winning star is close friends with fellow Brit James, who was recently forced to dismiss reports that 1D would be getting back together to commemorate his last episode at the helm of The Late, Late Show.
However, while a One Direction reunion did not come to fruition, the band did come up in the conversation when Harry took part in a game of Spill Your Guts Or Fill Your Guts, where James asks his guests difficult questions which they have to answer or consume a repulsive concoction.
During the game, James asked the Watermelon Sugar singer: “Yes or no, will there be a One Direction reunion?”
After a long pause, Harry insisted: “I would never say never to that. I think if there was a time where we all felt that that was what we wanted to do then I don’t see why we wouldn’t.”
Since embarking on his solo career, Harry has topped the charts on both sides of the Atlantic, and earlier this year won the coveted Album Of The Year prize at the Grammys.
Last year, he revealed there was still a “very deep love” between the five original members of One Direction, who shot to global fame after competing on The X Factor in 2010.
“I feel really lucky that we always had each other to be this unit that felt like you could keep each other in check and you could just have someone else who gets it,” he explained.
“Because it’s impossible to not, at times I think everyone experiences this, feel like, ‘Oh, everyone else is on the other side of the glass and I’m on this side of the glass, and no one really gets it’. And I think having that is kind of priceless.”
He added: “I think there is very much a respect between all of us, if we did something together. And that is something that you can’t really undo.
“And you know, it’s like a very deep love for each other, I think.”