In this publicity photograph released by ABC, host Katie Couric (left) interviews singer Sheryl Crow during the debut of her syndicated talk show Katie in New York.

London - Sheryl Crow thinks her benign brain tumour was caused by her cellphone.

The 50-year-old singer - who has previously battled breast cancer - claims no one will confirm that her usage of the device was what caused the tumour, but she feels like it might be behind it.

She said: “There are no doctors that will confirm that. But I do have a theory that it's possible that it's related to that. I used to spend hours on the archaic old cellphones.”

Initially, Sheryl was concerned she had Alzheimer's disease when she began forgetting song lyrics, but is glad the tumour is not of serious worry.

Speaking on Katie she said: “I was worried I had early onset Alzheimer's. It's nothing to worry about. But it was definitely a sobering moment.”

The Soak Up The Sun singer previously revealed it was memory loss which led her to get the problem checked out.

She said: “I worried about my memory so much that I went and got an MRI. And I found out I have a brain tumour.

“And I was, like, 'See? I knew there was something wrong.' I haven't really talked about it... But it's benign, so I don't have to worry about it. But it gives me a fit.” - Bang Showbiz