The 26-year-old proved an instant hit with viewers when he joined the BBC1 soap just a year ago to play the returning character Oscar Branning.
But he has quit and is set to follow Kellie Bright, 50 — who plays Linda Carter — and Ravi Gulati star Aaron Thiara, 33, out of the door later this year.
Meanwhile, 42-year-old Michelle Ryan’s character Zoe Slater — who first appeared in 2000 — is set to be killed off in coming weeks only a year after her comeback.
A source said: “Viewers are still reeling from the news they are losing Kellie and Aaron, two incredibly popular staples.”
Pierre was signed up by new EastEnders boss Ben Wadey, 32, who joined from Channel 4’s Hollyoaks last year.
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Pierre will film his final scenes at studios in Elstree, Herts, and the door is expected to be left open for the character.
The source added: “The fans love Pierre, so this is a huge blow to the show.
“It’s also interesting that signing up Pierre has been one of the better things that Ben Wadey has done.
“So the fact that he’s leaving is not a good look.
“Everyone’s now hoping that the rest of the cast will sit tight for a while.”
Last week we told how Zoe will die in her sleep after banging her head.
An EastEnders spokesman declined to comment.
