Rik Mayall was "happily chatting" to the son of British director Peter Richardson only half an hour before he died.
The comedy actor died yesterday, aged 56.
"He was happily chatting away [to my son] and then we still don't know quite what happened but it was a seizure of some sort," said Richardson on BBC Radio 4's Today programme.
In 1998, Mayall was left in a coma for several days after a serious quad bike accident. He recovered, but was left with epilepsy - for which he took daily medication.
"He had 16 years after the quad bike and I think that at the time people didn't think he would survive," added Richardson, who worked with Mayall on The Comic Strip Presents.
"But he lived for another 16 years and it was just shocking that he was so happy and seemed so healthy when he did go."
The cause of Mayall's death is still unknown, confirmed his wife, Barbara Robbin. The couple had three children together.
"We don't know yet what happened," she said. "He had a strong heart, so I don't think it was a heart attack. But we just don't know until the coroner's report.
"Maybe he had a fit, maybe it was his heart. We just don't know."
Richardson described his former friend and colleague as a "comedy pop star", and said that he had led a "happy life".
"He's got a very wonderful family, he was a very loving father and all I can say is that Rik had a very happy life," he said.
"He was such a star. There was only Rik. He loved playing the bad boy, in fact the badder the better. But he was a family man who did the washing up who was a very warm person. He wasn't as selfish and vain as he made out."
The director recalled one memory of his friend, which took place in the early hours as Mayall, Nigel Planer and Richardson were travelling back from a show in Portsmouth.
The group noticed a motorbike left in the road, which had left the driver in a "very bad state" and came to his rescue.
"We weren't sure if he was going to live or not," said Richardson.
"So Rik started doing bits from The Young Ones. So did Nigel. I just picture this guy thinking, 'I must have died and gone to heaven and The Young Ones were here to greet him.' He was fine in the end."