Actor John Ritter, most famed for his role as Jack in 1970s comedy series Three's Company, has died this morning.

The Emmy award winner, who would have turned 55 on Wednesday, collapsed on the set of ABC's 8 Simple Rules for Dating My Teenage Daughter late yesterday (Thursday).

He was rushed immediately to the Providence St. Joseph Medical Center but died shortly after 10pm EST (3am UK). The cause of death was a dissection of the aorta, the result of an unrecognized flaw in his heart, his publicist Lisa Kasteler confirmed.

Ritter was accompanied to the hospital by his wife Amy Yasbeck, 23-year-old son Jason, producers and co-workers.

He is survived by three other children, Carly, Tyler and Stella.