Joseph Gordon-Levitt gained "even more admiration" for Taylor Swift after singing her track 'Lover' on 'The Tonight Show'.

The 43-year-old actor felt "terrible" about having to be in New York to film his appearance on Jimmy Fallon's talk show last month because it clashed with his wife Tasha McCauley's birthday, so he decided to surprise his spouse - who had stayed in Los Angeles with their two sons - by serenading her with her favourite song.

He told People magazine: "I felt absolutely terrible and knew I needed to do something. And the night that I went to do Jimmy's show was her actual birthday...

"We didn't know if we would get the rights [to perform the song] because it's very difficult so I had to also pick a back-up and that was very difficult.

"I actually gained even more admiration for Ms. Swift as a songwriter as I was trying to find something else that would simultaneously be meaningful to my wife and meaningful to the wider world. It's a really hard balance to strike. She's a master, she's truly awesome."

The 'Beverly Hills Cop: Axel F' star's wife was delighted with the musical surprise.

He said: "Oh, she was shocked, yeah. In the best way. She sunk down into the couch squealing, I think...

"I think she would be embarrassed for me to say how big a fan of Taylor she is. We went to the 'Eras Tour' together. She's been a fan long before it was cool to be a Taylor Swift fan."

But Joseph knows his special birthday surprise for this year has set a high standard for him to follow in the years to come.

He laughed: "Here's the thing, though. The next year, I don't have to do it from New York.

"I get to do it in private, which is much easier."