01/08/2013 11:40 BST | Updated 01/10/2013 06:12 BST

'King Of Hollywood: Inventing David Geffen' PBS Documentary Reveals Gay Mogul's Devastation Over Love Split With Cher

David Geffen may have been able to reinvent himself many times over as the oft-acknowledged king of the entertainment industry, but there was one thing he could do nothing about - a broken heart.

And, even more intriguingly, it was a woman who devastated this openly gay tireless entrepeneur.

David Geffen and Cher were mutually infatuated following their first meeting at LA's Roxy Club

In PBS's absorbing documentary 'King of Hollywood: Inventing David Geffen', to be shown in the UK on Saturday evening, the music and film mogul explains how his relationship with Cher was "the greatest high I had ever experienced."

The pair met in the mid-1970s, at the Roxy Club in LA. As Geffen remembered it, "We fell madly in love."

The couple were together for 18 months, prompting a few raised eyebrows from their mutual friends.

"His friends thought I was too dumb for him, and my friends thought he was too square for me," is how Cher reports it in the documentary.

David Geffen's impressive roll call of artists included The Eagles, Jackson Browne, Neil Young and Joni Mitchell (above)

"There's been a few odd couples," says Elton John, one of Geffen's many, many high-profile signings and longtime friends. "And that's definitely up there amongst them."

At least, until Cher ultimately fell for the man who would be her next husband, Greg Allman, leaving Geffen broken-hearted, but ultimately philosophical.

"There was an article in Esquire magazine," remembers Geffen now. "Asking, 'Who is man enough for this woman?' ... and clearly I was not."

Despite their split, the pair have remained constant friends, with Cher speaking fondly of Geffen in the programme. "He was the most loving boyfriend in the world, the biggest cheerleader."

David Geffen and Cher have remained close friends, following their split in the 1970s

Geffen's extraordinary career is explored in the film, which follows him from his Brooklyn childhood, via the William Morris agency mailroom, to the highest echelons of Hollywood, where he has run a record label, produced films, and co-founded Dreamworks with Steven Spielberg and Jeffrey Katzenberg. He is estimated to be worth more than $5billion.

"I've always thought that each person invented himself for whatever reason, through whatever circumstance, whatever he has gone through, that we are each a figment of our imagination," is how he explains it.

"And some people have a greater imagination than others..."

'The King of Hollywood: Inventing David Geffen' is on PBS America (Virgin 243 Sky 534) on Saturday 3 August at 8pm. Watch the trailer below...