Richard Biggs, one of the actors in the cult science fiction TV series Babylon 5, has died in the US aged 44.
Babylon 5 was a cult US science fiction series in the 1990s
Biggs, who played Dr Stephen Franklin in the series and its three TV movie spin-offs, died on Saturday from a suspected aneurysm or stroke.
Series creator J Michael Straczynski said: "He woke up, got up out of bed - and went down."
Biggs, married with two sons, also appeared on ER, NYPD Blue, and the soap Days of Our Lives.
Paramedics who treated the actor at his California home suggested a "massive stroke" or aneurysm had been the cause of his death, Mr Stracyznski said.
He described Biggs' death as a "terrible loss. Richard was a consummate professional, but more than that, he was an honourable, stand-up guy," he said.
Since 2001, Biggs had also appeared on the CBS show Guiding Light.
His role as Dr Marcus Hunter on Days of Our Lives won him a Soap Opera Digest award as best supporting actor.
As well as his acting roles, Biggs also taught, notably at the Will Geer Theatricum Botanicum in Topanga, California, where a memorial service will be held.