Paul Nicholls has left BBC One drama Waterloo Road after just three days of filming.
It is said that the former EastEnders actor, 32, "wasn't in the right place" to film the scenes following the death of his grandfather, to whom the star was very close, just before the start of production.
Paul, who was reprimanded once for being late, has been replaced by The Bill star Alex Walkinshaw in the role of PE teacher Jez Diamond.
A source said: "Paul wasn't in the right place to do it. It was causing concern. It became clear to both sides that it was really time to call it a day. Ultimately, it was Paul's decision to go."
The actor found fame at 16, as troubled Joe Wicks in EastEnders, when he was twice voted TV's sexiest actor.
He quit the soap after two years and went straight into the TV series City Central, but asked for his character to be written out.
He was quoted as saying afterwards in an interview: "I was well on my way to a total breakdown. I was drinking a lot and taking drugs. I had lost control of my life."
Paul quit drugs and drink, and this year has enjoyed TV roles in Secret Diary Of A Call Girl and Candy Cabs and the independent feature film Life Just Is.
A BBC spokeswoman denied a report that the actor was sacked, saying: "Paul Nicholls has left the production of Waterloo Road, currently filming in Rochdale.
"The producers of the show, Shed Productions, said the actor's decision was for personal reasons following a recent family bereavement. The role of Jez Diamond will now be played by Bill actor Alex Walkinshaw."