TV presenter Matt Richardson said he was admitted to hospital after suffering from memory loss.
The 31-year-old, who competed on Dancing On Ice last year, shared a photo of himself at a Green Day concert in Marlay Park, Dublin, last week alongside his brother.
However, he said he was unable to remember the gig after developing “loads of amnesia” because of an unspecified infection.
“And I sadly can’t remember it as I’ve had a lovely infection which caused some wonderful affects to my brain and loads of amnesia.
“After a really cool trip to hospital I’m trying to piece it all together again.
“Hopefully the memories come back but if I owe you money, sorry you’re on your own.”
His post prompted concerned friends to send messages of support.
Love Island presenter Laura Whitmore commented, “Hope you’re ok!!!” while stand-up comedian Lauren Pattison added: “Get well soon champ”.
Richardson presented ITV2 spin-off show The Xtra Factor alongside the late Caroline Flack in 2013.
He has since served as a drive-time presenter on Virgin Radio UK and co-presented Celebrity Haunted Hotel Live and Celebrity Haunted Mansion with Christine Lampard.