Writer director Richard Curtis has dropped off of an upcoming Bee Gees musical biopic because he found the project "too sad."

Curtis tells Britain's The Sun, "I was going to write a musical of the Bee Gees, but too many of them have died and it got really sad. It was going to be with Steven Spielberg."

Maurice Gibb died in 2003 at the age of 53 and Robin Gibb died in 2012 at 62 after a prolonged struggle with cancer and other health problems.

It is not yet known who will replace Curtis. Remaining Bee Gees star Barry Gibb has signed on as producer.

The Bee Gees have sold more than 220 million records worldwide. They were inducted into the Rock and Roll Hall of Fame in 1997.