Taron Egerton collapsed on the opening night of new theatre show

Taron Egerton had fans and viewers fearing the worse when he fainted on stage during the opening show of his new theatre production, Cock.

The 32-year-old actor took to the stage at London's Ambassadors Theatre on Saturday evening, but collapsed, and his understudy, Joel Harper-Jackson, stepped in to replace him in the final segment.

The Kingsman and The Golden Circle star has made light of the incident, as he joked his performance was "electrifying", so much so, his body "couldn't handle it".

Taking to his Instagram account, the Rocketman star reassured worried viewers he is fit and well. Sharing a screengrab of a note he penned on his Instagram Stories, he wrote: "I am completely fine. Slightly sore neck and a bruised ego, but I'm fine."

"As some of you may have heard, I passed out during the first performance of COCK last night", he continued.

"I've decided to put a positive spin on it and I would appreciate it if anyone who was in the theatre last night just said that I gave such a committed, electrifying performance that my body couldn't handle it and check out.

"That being said, apparently you're meant to actually do the full show and not just three quarters of it. So I'll be back with a vengeance tomorrow night.

"Thank you to the amazing team at the theatre and my wonderful cast mates for being so lovely.

"But mainly I wanted to say thanks to Joel Harper Jackson who stepped in to do the last bit of the play.

"Joel is an amazing actor and a lovely person. Thank you, Joel. T x."

The production company has shared a doctor, who was in the audience, immediately tended to Taron.

The statement, which has been obtained by The Sun Online, read: "During this evening’s first preview of Mike Bartlett’s play Cock at the Ambassadors Theatre, Taron Egerton fainted towards the end of the performance.

"A doctor who was in the audience attended to Taron immediately after the incident and, whilst he felt fine, it was decided that Taron’s understudy, Joel Harper-Jackson, would continue in the role to complete the performance."

Taron will reprise his role as M, on Monday evening.

Cock depicts the love story of one couple John - played by Jonathan Bailey - and on-screen boyfriend M, acted by Taron, navigate their romance, only for it to be turned on its head when John falls for a woman, portrayed by Jade Anouka.

Rest up Taron!