Credit: Josiah Kamau/Getty Images

Before Adele’s new album 25 hit shelves on Friday, the only two songs she previewed were her smash hit “Hello” and a live performance of “When We Were Young.” Since the album’s release, “When We Were Young” has been hailed as a standout track, and Adele gave an emotional, powerful performance of the song on Saturday Night Live.

That track was co-written by Tobias Jesso Jr., who penned it with Adele. Jesso, a longtime Adele fan who released his debut album, Goon, in March, took to Facebook on Saturday to write about what it was like to team up with his “favorite singer/songwriter.”

“When I got the call that I would be working with her, my heart stopped,” Jesso wrote. “I spent four years in Los Angeles trying to write songs for anybody I could get to hear them, and eventually, as some of you know, I had to start singing them myself just to get them on a record. I was nervous as s— as anybody would be with someone like Adele walking in the room and being my first professional collaboration I would ever have.”

Jesso added that he was entirely starstruck when he first met the singer, but the pair quickly teamed up to start collaborating. The admiration between the two is mutual, as back in January, Adele tweeted a link to Jesso’s song “How Could You Babe,” calling it “fantastic.”

“There was no studio, just a piano and us, and we wrote a lot,” Jesso wrote. “I mean a lot lot. I learned a lot from her, most of all just how much she truly deserves to be exactly where she is, and why all of her songs mean so much to the people who hear them. I can tell from the bottom of my heart she means what she says and the words she puts into her music. Every lyric and every line comes from a place that she feels. She does not settle.”

Read Jesso’s full post below.