The craniopharyngioma growth was discovered on his pituitary gland earlier this year, he said in an Instagram post, after the onset of "intense localised headaches" and a "weird fatigue" towards the end of 2023.

Sharing a picture from his hospital bed, McBriar said he underwent surgery on 9 August and the operation well.

The tumour is "almost certainly not cancerous", he said, and was caught "in the earlier stages of damage".

Bicep, from Northern Ireland, have performed throughout the spring and summer, including sets at Glastonbury and Coachella, with more festivals scheduled in August and September.

They cancelled their appearance last minute at the Boardmasters festival in Cornwall at the weekend.

In his Instagram post, shared with the duo's 397,000 followers, McBriar said: "I got several blood tests in spring 2024 which came back indicating that something was wrong, so my GP arranged an MRI followed by a CT scan.

"Unfortunately, they told me they had discovered a large, and pretty rare Craniopharyngioma tumour on my pituitary gland [in my brain]. The good news is firstly, it's almost certainly not cancerous and secondly, I've caught it in the earlier stages of damage.

"I'd been very lucky to get those initial blood tests followed by an MRI. Had it been much longer I might've lost some eyesight and a load of other problems due to the size and position of the tumour pressing on my optic nerves."

McBriar said he had been through "many rounds of hospital appointments and tests" before having surgery.

"I decided to carry on living life and playing shows as normal and it was personally important to keep my mind busy," he wrote. "The operation went well and I'm currently recovering in hospital.

"Recovery will be at least 6-8 weeks and a long road of aftercare but I'm feeling incredibly grateful and lucky."

McBriar thanked medics who have "been so amazing, kind and empathetic", saying his care had been "incredible", with appointments arranged "with sometimes only hours' notice".

He added: "Our healthcare system is very precious and worth fighting for!"

Andy Ferguson, his Bicep partner, will continue to perform solo as Bicep while he recovers, he said.

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The duo are childhood friends who have become one of the biggest acts in dance music. Bicep released their self-titled debut album in 2017, featuring the hit track Glue, followed by Isles in 2021, which reached number two in the UK album chart.

According to Cancer Research UK, craniopharyngiomas are benign, or non-cancerous, brain tumours which usually grow near the base of the brain, just above the pituitary gland.

In adults, they make up less than 1% of all brain tumours, the charity says.