Taylor Swift has revealed her mother Andrea has been diagnosed with a brain tumour.

The pop star, whose latest album Lover features a song about her mother’s battle with cancer, said it is her mother’s health that has contributed to her decision to play festivals including Glastonbury this year.

She told US trade magazine Variety: “I wanted to be able to perform in places that I hadn’t performed in as much, and to do things I hadn’t done before, like Glastonbury.

“I feel like I haven’t done festivals, really, since early in my career — they’re fun and bring people together in a really cool way.

“But I also wanted to be able to work as much as I can handle right now, with everything that’s going on at home. And I wanted to figure out a way that I could do both those things.”

Asked if being able to be there for her mother was the main concern, she said: “Yeah, that’s it. That’s the reason.

“I mean, we don’t know what is going to happen. We don’t know what treatment we’re going to choose. It just was the decision to make at the time, for right now, for what’s going on.”

She added: “Everyone loves their mom; everyone’s got an important mom.

“But for me, she’s really the guiding force. Almost every decision I make, I talk to her about it first. So obviously it was a really big deal to ever speak about her illness.”

It was while Swift was filming for her upcoming Netflix documentary Miss Americana that Andrea’s cancer returned for a second time, and the singer said: “She was going through chemo, and that’s a hard enough thing for a person to go through.

“While she was going through treatment, they found a brain tumour. And the symptoms of what a person goes through when they have a brain tumour is nothing like what we’ve ever been through with her cancer before. So it’s just been a really hard time for us as a family.”