Tammy Faye Bakker was a chirpy, perky televangelist noted for her lavish mascara and her barrel-stave eyelashes. She once conducted an interview on her PTL (Praise the Lord) chat show for which she remains revered among gays.

It was in 1985 and she was talking to Steve Pieters, a soft-spoken church pastor with a soup-strainer moustache. He had Aids, a disease that killed Rock Hudson that year and was scything through Reagan’s America. Tammy wanted to know all about Steve’s faith, his health and his orientation. ‘Have you given women a fair try?’, she asked rather naively. The pastor told his story and the interview deepened into an extraordinary confessional. He was facing death bravely but he simply couldn’t bear the thought that no one would ever touch him again and that he would die un-hugged and alone.

As Tammy watched him on telly link-up – the poor man was too ill to travel to the studio – she comforted him as best she could. Her tears flowed unbidden: ‘I wanna tell you that there’s a lot of Christians here who love you and wouldn’t be afraid to put our arms around you and tell you that we care.’

As for her network audience, many were doubtless thinking the opposite: that for this sinning pastor, God’s judgment was coming and right soon. (Amazingly, Pieters ultimately recovered and is still preaching.) But the effect of the interview was electric – and lasting. Tammy knocked America a degree off its axis and from that day on she became the bubbly, kitsch patron saint of American gays and lesbians.

Tammy, who always stuck up for the sick and outcast, was a female counterweight to her brimstone male colleagues, notably the ball-busting Reverend Jerry Falwell who denounced Tinky Winky in the Teletubbiesas a sick homo. Falwell was a notorious kerb crawler and Jimmy ‘I have sinned’ Swaggart was no less unpleasant.

Tammy and her husband Jim Bakker’s story is remarkable, however, for its descent into chaos. The show developed a new style, with singing and dancing, celebrity guests, Tammy making fudge for Jesus and so forth. Mad as that sounds, in the US it delighted a whopping audience of some 13 million and went on to become an empire.

But the reality was not all happy or clappy. Tammy existed in a vortex of scandal, marital meltdown and dodgy tax returns. She died in 2007 but showbiz can’t seem to leave her life alone. Last year there was a film, The Eyes of Tammy Faye, starring Jessica Chastain, a competent, if inane,biopic. It was based on a lurid documentary of the same title. There was a film in 1990, Fall From Grace, partially redeemed by Kevin Spacey, who was riveting as Tammy’s cheesy felonious husband Jim. There have been several American fringe plays about her. What a shame the late Angela Lansbury never played her.

This side of the pond, however, few have heard of Tammy Faye. That’s about to change, thanks to a new musical with a score by Elton John. It stars Katie Brayben (terrific in the Carole King musical Beautiful) as Tammy. The book is by the ubiquitous dramatist James Graham, who wrote the BBC series Sherwood and the play Ink about Rupert Murdoch, and the lyrics are by Jake Shears, lead singer of the band Scissor Sisters.

Shears, an American, is a great mate of Elton’s. His parents were Christians but they didn’t watch the PTL channel. Their little son, however, did. ‘I think they were bemused by my fascination with her,’ he told me. ‘When yourseven-year-old is obsessed with Tammy Faye, Dolly Parton and Zsa Zsa Gabor… there’s a high chance you’ve got a gay kid! Tammy preached true Christianity and she preached true love.’

Behind the eyelashes and face bronzer (which apparently left an indelible imprint on your shirt like the Turin Shroud when she hugged you) she was linked to crooks. Her story is indeed one of large-scale fraud and hucksterism. She and Jim Bakker met at Bible college. They spent their lives building up a ministry empire with a satellite network and a vast theme park called Heritage USA in Southern Carolina. It had hundreds of hotel rooms, a Noah’s Ark Toy Shoppe and a tasteful recreation of the dining room of the Last Supper.

Jim Bakker estimated PTL’s fundraising goal was at one point $1 million per week. Heritage USA was visited by a staggering six million people a year, making it almost as popular as Disneyland. Through the tills and the telethons, money cascaded in. Tammy and Jim spent a fortune, living a flashy life that perfectly aligned with the prosperity gospel they preached. God wanted everyone to be healthy and wealthy and so they zoomed about in jets and gave their pets lifestyles of film star luxury. Little miracles happened. When Tammy had a wart on her finger, she would dunk it in communion wine. When she removed her pinkie it would be gone. Praise be!

But the PTL’s spinning top started to wobble. Financial irregularities cropped up. Bakker paid $265,000 in hush money to a young secretary, Jessica Hahn, who accused him of rape. Jerry Falwell offered to help the Bakkers by suppressing the Hahn story as long as they handed over their business, but Falwell hijacked it instead while smearing Jim as a pervert. Jim Bakker got 45 years for defrauding supporters of $158 million. He served five.

Tammy – who must have had at least some idea of what was going on – was endlessly lampooned by late-night satire shows (depicted with her mascara invariably ruined by crocodile tears) and ended up in rehab for prescription drug addiction. After divorcing Jim while he was in prison, she married Roe Messner, a relentless church builder and the developer of the theme park, who was in turn convicted of bankruptcy fraud and did two years’ jail time.

Tammy’s career nosedived – she ended up on the Fox network co-hosting a show with a nice gay actor. ‘When we lost everything it was the gay people that came to my rescue and I will always love them for that,’ she told American TV host Larry King in her final interview shortly before her death from cancer in 2007.

‘I think like a lot of other gay guys that grew up in the Christian world, she was a fresh breath of air. Someone who would accept you as you are,’ says Shears. Tammy Faye undeniably brought a twinkly glamour plus some actual moral support to the televangelists’ shouty trade.

Brace yourself for a musical of even more than the usual campness.