Joe Manganiello has undergone "extremely serious" surgery for appendicitis.
The 'Magic Mike XXL' actor went into hospital late last week to have his appendix removed, but doctors were "alarmed" by his condition when he was admitted.
Though it is not clear what the problem definitely was, a source told TMZ his appendix has burst.
It is believed the 39-year-old star is still in hospital.
The news comes after it emerged Joe and wife Sofia Vergara pulled out of hosting a charity event on Sunday (17.04.16) because of his ongoing medical issues, which were originally believed to be due to the same ongoing chronic issue which saw him withdraw from an Upcoming History Channel series 'Six'.
The couple had been booked as honorary co-chairs at a benefit for Stuart House Benefit, a facility which help victims and those affected by sexual abuse.
Fashion designer John Varvatos, who hosted the event, said: "Joe's been a big part of what we've done over the years. He's been a great personal friend. He's been involved in all of our - the last four or five years - our Stuart House events.
"Basically they just couldn't make it because [Manganiello] is recovering.
"I don't know a lot about it other than that he's had a little bit of a health problem. We wish him the best. We thank him for all his support that he's given us and, most importantly, to get well soon because he's such a wonderful guy."
No official reason was given when the 'True Blood' hunk - who had surgery on a torn bicep while shooting 'Magic Mike XXL' - pulled out of 'Six' but it was reported he was unable to cope with the "physical demands of the role" due to a "manageable pre-existing condition".
Tagged in Sofia Vergara Joe Manganiello