He said: "I thought I was having a heart attack. I had this bug and at about 2am I had to wake Jenny up. We were filming the Christmas special up in Glasgow.
"I said to her, 'You should call an ambulance.' We called the ambulance as we wanted to meet them on the street. When Jenny and I were in the lift we were still on 999. They told her to put her hand on my tonsil, to count my heart beat.
"It was all going on. I had the fright of my life and I thought I was a goner. When I got in the ambulance they said, 'Well it is not your heart ' and I vomited it out for 12 hours. I had a very violent bug."
News of his woes come shortly after his long-time co-star Rory Cowan made the shock decision to quit the show but refused to give the reasons why.
The actor, who performed for the last time at London's O2 on Sunday night, told the Irish Daily Mail that he has been unhappy for some time.
He said: "I hadn't been happy working for the Mrs Brown's Boys company for the last 18 months to two years. I feel that 26 years is enough so I decided to go. I told Brendan on June 16 about my decision to leave. That's when I handed in my notice.
"I was supposed to leave at the end of that week, but Brendan said that would be impossible and asked if I'd stay on until the end of the London O2 gigs. So I agreed to that."
Mrs Brown's Boys started off as a stage show before being picked up by the BBC and becoming a TV smash hit.
It first aired on the channel in 2011 to huge acclaim and a movie, called Mrs Brown's Boys D'Movie, was released three years later.
The show's live tour is scheduled to hit New Zealand in March.