Actor Joe Alwyn has said he is proud of the music he and girlfriend Taylor Swift wrote together in lockdown.

The London-born star, 31, has been dating singer-songwriter Swift, 32, since at least 2017, but the pair have remained intensely private about their relationship.

Alwyn will next be seen in a BBC series adaptation of Sally Rooney’s debut novel Conversations With Friends, which airs on BBC Three and iPlayer from May 15.

Joe Alwyn is GQ Hype’s cover star (Fumi Homma/PA)

He worked with Swift on her surprise eighth studio album Folklore, writing under the pseudonym William Bowery, and co-wrote a number of songs on the follow-up sister album, Evermore.

He told GQ Hype about writing songs in lockdown: “It was really the most accidental thing to happen in lockdown. It wasn’t like, ‘It’s three o’clock, it’s time to write a song!’.

“It was just messing around on a piano and singing badly and being overheard and then thinking, you know, what if we tried to get to the end of it together?”

The actor – who gained recognition after starring in 2016 war drama Billy Lynn’s Long Halftime Walk, which was directed by Ang Lee and also starred Kristen Stewart – said of writing with Swift: “It was fun to do it together, and I was proud of it.

Joe Alwyn spoke to GQ Hype about BBC series Conversations With Friends (Fumi Homma/PA)

“It was nice getting such a positive reception.”

Conversations With Friends follows two Dublin college students, Frances and Bobbi, as they forge a strange and unexpected connection with married couple Melissa (Jemima Kirke) and Nick (Alwyn).

The 12-part series is being made by the producers of Normal People, the hit series based on another of Irish author Rooney’s books.

Alwyn said of Nick’s accent: “I listened to people like Andrew Scott and Tom Vaughan-Lawlor and that kind of middle-class south Dublin accent.

“(Nick’s’) is quite anglicised, there was the idea that he would have been to drama school in London and he has a British wife and so maybe some of those sounds have been softened as well.”

The screen adaptation of Normal People was a huge hit and its stars – Paul Mescal and Daisy Edgar-Jones – received critical acclaim.

The full GQ Hype interview with Joe Alwyn is available online.