Friends almost lost Jennifer Aniston halfway through the season

Jennifer Aniston almost didn't appear on Friends, according to a new book about the hit show.

The book, Generation Friends, claims that the writers were close to recasting Rachel green because of a scheduling clash, The Sun reports.

Aniston had already filmed numerous episodes of a show called Muddling Through before she auditioned for Friends in 1994.

The NBC network's concern was that Aniston's role on the rival network would be picked up for a full season, and she'd be forced to leave Friends midway through the first season.

According to the book, the network went to extreme lengths to secure Aniston for the role of Rachel. They apparently endeavoured to "kill" Muddling Through by sneakily scheduling blockbuster movies at the same time the show aired to ensure it didn't generate a big audience.

Muddling Through was eventually canned, and Aniston proceeded to star in 10 seasons of Friends.

The book also reveals that the network initially wanted a "seventh friend" to star alongside Rachel, Monica (Courteney Cox), Phoebe (Lisa Kudrow), Ross (David Schwimmer), Chandler (Matthew Perry) and Joey (Matt LeBlanc).

"The one major suggestion the network had was the addition of an older secondary character," author Saul Austerlitz wrote.

The writers of the show considered the character known as 'Pat The Cop', but ditched the idea after realising that a seventh member of the crew wouldn't work.

"The writers made a good-faith attempt, even casting the role, but hated the resulting script so much that they pleaded with NBC to drop the idea," reveals the book. "NBC gave its permission and Pat the Cop was no longer."

Other interesting facts that are explored in the novel is the fact that the show was almost titled Friends Like Us, the TV executives initially fought for a more racially diverse cast, and that Joey was meant to be an intelligent character.