The 32-year-old actor plays male nurse Dan Goldman in the Seven Network drama.

The news has rocked the cast and crew of the long-running show. One source told smh.com.au the mood was one of "numb shock".

The Seven Network has confirmed that Priestley took his own life.

Tuesday's episode of the show, in which Priestley's character Dan Goldman married nurse Erica Templeton (Jolene Anderson), was watched by 1.282 million viewers.

A Seven Network statement described Priestley as "a tremendous young person - loved and respected by his fellow All Saints cast members and crew".

Seven's director of programming and production Tim Worner described him as a "brilliant artist".

"His work on stage and screen was admired by everybody who knew him," Worner said.

"His death is such a sad loss. We at Channel Seven will miss his energy and smile.

"Our thoughts and prayers are with Mark's family and friends."

Priestley graduated from NIDA in 1999.

His credits include roles in the critically acclaimed miniseries Changi, and the television drama series The Secret Life Of Us and Blue Heelers.

He joined the cast of All Saints in 2004.

He has also worked with the Bell Shakespeare Company and the Sydney Theatre Company.

Actor Jolene Anderson hurt in car crash

All Saints actor Jolene Anderson has been injured in a car accident.

Seven has revealed that Anderson, who played Priestley's wife in the TV drama, injured her arm in a car accident yesterday.

"Jolene was driving yesterday, and the car she was driving was hit by a truck," a Seven spokeswoman said.

"She walked away from the accident but is having further X-rays today."

Anderson, who is performing in the musical Tell Me On A Sunday, was forced to miss her show last night and won't perform tonight, the spokeswoman said.

It's the latest in a string of incidents to rock the All Saints cast.

Cast member Virginia Gay was allegedly mugged in Sydney in June.

Her alleged attackers also have been charged with murder over the bashing death of a chef.

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