He announced the upcoming release of his tell-all memoir last week, which is set to detail his decade-long stint on Friends and his private battle with addiction which tainted his hugely successful career.

Teasing a snap of the front cover of his upcoming book titled, Friends, Lovers And The Big Terrible Thing, Matthew Perry, 52 – who played Chandler Bing on the hit show from 1994 to 2004 – Tweeted, "So much has been written about me in the past. I thought it was time people heard from me. The highs were high, the lows were low. But I have lived to tell the tale, even though at times it looked like I wouldn't. And it's all in here," jokingly adding, "I apologise it's not a pop-up book."

The troubled actor – who was paid a seven-figure sum to publish his life story – is said to have penned "one of the juiciest reads in years" amid reports that "no topic is off-limits" as he takes fans behind the scenes of the most successful sitcom of all time which shot him to global stardom.

And insiders tell Closer how his latest announcement has ruffled feathers for his former co-star and pal, Jennifer Aniston, 53, who is anxious about what Matthew could spill about her own private life, particularly her high-profile divorce from Brad Pitt in 2005.

The The Morning Show star was left heartbroken when her husband fell for Angelina Jolie on the set of 2004 film Mr & Mrs Smith, going on to marry and have six children with the actress, who he's since split from.

Brad's reported affair came as Jennifer wrapped the final scenes of Friends and admitted she was hoping to start trying for a family with the Fight Club star.

Matthew attended the pair's Malibu nuptials in 2000 and spent a lot of time with Brad, who made a guest appearance on the sitcom in 2001.

JEN AND BRAD IN 2000 ©GETTY IMAGES

The source says, "Jen's anxious, and it's with good reason given Matthew knows so much about what went on in her private life and knew intimate details about her marriage.

"While the show ended the year before their divorce, Matthew was with her during the breakdown of the marriage, and witnessed not only her heartache and turmoil but private details she's never publicly revealed – which she is now petrified he will spill himself.

"He hasn't suggested that the book will include private details about anyone else, but Jen knows Matthew will want a bestseller and, to achieve that, he'll need to expose as many juicy secrets as possible. And being privy to one of the most high-profile showbiz splits in history, he knows that will be something everyone will want to know about."

Matthew and his five co-stars, David Schwimmer, 55, Matt Le Blanc, 54, Courteney Cox, 57, and Lisa Kudrow, 58, and Jennifer, became "inseparable" as they lived in each other's pockets working together every day for a decade – forging close friendships both on and off screen.

THE FRIENDS CAST ALONGSIDE JAMES CORDEN IN 2021 ©GETTY IMAGES

But while the girls remained close – with Jen and Courteney still long-term BFFs to this day – they grew apart from the boys, which Jen seemingly confirmed when she didn't invite her male co-stars to her 2015 wedding to Justin Theroux, who she divorced in 2018.

During their highly anticipated reunion last year, Matthew dryly joked about how he doesn't hear "from anyone" as the six admitted they'd only all been together in the same room twice since the show wrapped 17 years ago.

And insiders say having grown apart has further sparked Jen's anguish over what Matthew could reveal.

The source says, "While pals have tried to calm her nerves by insisting Matthew would never betray her, she is acutely aware that she's barely spoken to him over the last few years and that close bond they shared has very much dissipated.

"While there's been no big fallout, it's made Jen feel very much on edge given there would no longer be a friendship to lose if he spilled the beans on her private life."

Last year, the actress revealed she didn’t fully realise the “self-torture” Matthew felt while filming the series, in which he secretly struggled with substance abuse.

Following a stint in rehab in 1997 for his painkillers and alcohol addiction, he returned after relapsing in 2001, and has been sober ever since.

But fans speculated about another relapse following the reunion show last year because of Matthew’s puffy face and slurred speech, which he insisted was down to some invasive dental work.

Just seven weeks after the reunion show aired, Matthew – who’s never been married or had children – split from his fiancée, Molly Hurwitz.

Insiders at the time told Closer how his worried co-stars rallied round him to offer support, fearing the split could lead him to spiral again.

And the rest of the cast have also been left wondering about Matthew’s upcoming revelations. The source says, “Courteney, Lisa, Matt and David are also worried about what Matthew could spill about their lives too, so all of them are very much on edge.

“Matthew’s been through hell and back over the years and while they know it’s important for him to tell his story, they’re just praying he shows them the loyalty they showed him and this book doesn’t destroy the bond they’ve all cherished for the best part of 25 years.”