Danny O'Donoghue was hospitalised with a heart problem after going out drinking with Sir Tom Jones.
The Script singer had been working on auditions for 'The Voice' with the 84-year-old icon in Manchester when they ended up staying awake all night drinking champagne, with the 'Last TIme' hitmaker desperate to keep up with his new showbiz pal.
He recalled to BBC Radio Wales: "It was after one show on The Voice and we were in the Lowry [hotel] up in Manchester and we went drinking that night, and he was telling me all these stories about Elvis and the Rat Pack and every time the champagne got to like a certain level, he'd be clicking [his fingers] to get another bottle of champagne.
"And he said you can't leave the table until the champagne is done. And it just wouldn't stop."
"We're probably there six hours or something from 12 o'clock to six in the morning.
"And I just remember thinking 'what's all the clinking going on' and they were putting out the things for breakfast in the morning."
Danny eventually went to bed but when he woke up, he knew there was something wrong and found his "heart had flipped into a different rhythm".
He added: "I didn't know what was going on so I went to the hospital - and I got atrial fibrillation, external from drinking nothing but champagne for six hours."
Atrial fibrillation is described as a heart condition that causes an irregular and often abnormally fast heart rate.
As a result, the 43-year-old star "missed one or two days of filming" on 'The Voice', on which he was a coach for two seasons in 2012 and 2013.
He added: "It was my fault because I should have stopped drinking very early."
Danny hailed Tom a "super guy".
He added: "I don't mean to age him but he's from the same era as my dad but he's a man's man, grew up in the coal mines, loves songs, loved drinking.
"What an amazing career that guy's had.
"And like all Welsh people they're so down to earth, it's easy to forget how big and how legendary Tom is but he makes you feel that way himself, but I really, really loved my time with him."
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