O'Sullivan's family says the 48-year-old _ a well-known presence on the Canadian stage _ died Friday.
A longtime performer with the Second City improv troupe, O'Sullivan also appeared on the small screen in shows such as "Little Mosque on the Prairie," "An American in Canada" and "Murdoch Mysteries."
His partner, the actor Linda Kash, is currently performing in "Lost In Yonkers" at Toronto's Jane Mallett theatre.
The show has been put on hold until Wednesday in the wake of his death.
Police say Friday's crash occurred around 2:30 p.m. after a vehicle left the road, crossed the shoulder and struck a parked flatbed pickup.
A visitation is planned for Saturday at 11 a.m. at the Highland Park reception centre in Peterborough, followed by a memorial service at 1 p.m.
(CKRU, The Canadian Press)
Note to readers: This is a corrected story. A previous story mistakenly said O'Sullivan was 47 years old.
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