The 31-year-old, who competed on Dancing On Ice last year, said he had developed “loads of amnesia” that has left him trying to piece memories back together.
The comedian shared a photo of him and his brother at a Green Day concert at Marlay Park in Dublin last week, which he is unable to remember.
Matt wrote: “My brother and I went to see Green Day in Dublin last week.
“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.”
Matt received lots of well wishes on his post, with Love Island presenter Laura Whitmore commenting: “Hope you’re ok!!!”
Matt is perhaps best known for his stint presenting 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.