Ryan Tedder thinks Harry Styles is a "phenomenally talented writer".
The OneRepublic frontman has been in the studio with the One Direction singer and has nothing but nice things to say about the experience, calling the hunky singer chilled out and so "unaffected" by his fame.
Speaking to Key 103, the 36-year-old songwriter said: "You know, he's a phenomenally talented writer. You know they say you can't judge a book by its cover, but clearly the man has taste in a number of areas and that also is true with writing.
"He's just a chill guy. I don't think I've met anyone with that level of fame that is that unaffected by it."
However, the 'Counting Stars' musician isn't sure what will come of the stuff they've made together.
He said: "We've done a couple of things; I have no idea what they're for. I don't know if he's doing an album, I truthfully don't. It started with he got spotted walking into the hotel I was in, walking to go up to my room, which was where my studio was set up.
"So obviously you can draw your own conclusion; he wasn't coming up for cognac and a cigar. So, yes, we've written a couple of times. I would love to write with him in the future for no other reason than he is one of the chillest dudes I've hung with and down to earth."
And Ryan's not the only person to have collaborated with Harry.
Snow Patrol's Gary Lightbody and Johnny McDaid have also casually worked with Harry on solo music, which will "surprise" fans of the pop star.
He told BANG Showbiz: "Gary and I have both written with Harry. Gary wrote on the second to last One Direction album 'Four'. We have worked with Harry he is a really great guy. I think he will surprise people. I don't know much about what he's going to do or his plans but he's a really lovely guy."
Tagged in Gary Lightbody Ryan Tedder Harry Styles