Hollywood A-listers Sylvester Stallone and Eddie Murphy were once close friends, but that all changed after one blowout feud in the late ’80s.

The little-known story behind the friendship’s demise is detailed in a new book by film journalist Nick de Semlyen, Wild and Crazy Guys: How the Comedy Mavericks of the ’80s Changed Hollywood Forever.

According to the New York Post, the book cites a rumored affair between Murphy and actress Brigitte Nielsen, then Stallone’s wife, as the the catalyst behind the friendship-ending fight.

The two actors had reportedly been great friends, and were even working together on a pitch for a third Godfather film before the feud broke out. The film, which would have starred Murphy and Stallone along with Al Pacino, was never made.

Trouble allegedly began after Murphy hired Nielsen to play the villain in his 1987 film Beverly Hills Cop II, sparking rumors that Murphy and his co-star were romantically involved. While Murphy denied the allegations, Stallone wasn’t convinced, and reportedly confronted his former friend in what the book describes as a blowout phone call from which the friendship never recovered.

According to de Semlyen, Murphy “caused plenty of drama” outside of the Stallone feud as well, and the new book chronicles a number of other little-known incidents that went on behind the scenes of some of the most iconic films of the 1980s. In addition to the Murphy incidents, de Semlyen details behind-the-scenes drama involving Bill Murray, Dan Aykroyd and Harold Ramis while filming classics like Ghostbusters and Groundhog Day.

The new book is expected to hit shelves on May 28.

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