United Kingdom, July 13 -- Richard Dreyfuss has been diagnosed with viral bronchitis.

The 77-year-old actor has announced via social media that he's withdrawn from a fan convention after contracting the illness.

In a video shared on the SharkCon Instagram page, Richard said: "Hello cons, I'm very, very sorry to tell you that I've been diagnosed with viral bronchitis. And I've been told by my doctors I cannot fly, and I would have to fly five hours to get there.

"I'm terribly sorry because I had planned to be there and had been looking forward to it."

The themed event - which is being sponsored by National Geographic - is being held in Florida this weekend.

In his video message, Richard explained that he "didn't want to get anyone els...