Wayne and Coleen Rooney made heroes of Lord of the Rings spoof

Once upon a time in a land far, far away (well, Liverpool), there was a heroic warrior called Wayne and a beautiful princess named Coleen... That, anyway, is the story of a new spoof fairytale fantasy show by one of the writers of TV's Motherland, who says it's her homage to the Rooneys.

Wayne and Coleen Rooney's life story has some elements of an epic saga - they have stuck together through thick and thin, and have both vanquished some formidable foes (him on the football pitch, her in court).

So creating a stage show that makes them characters in a fantasy world loosely inspired by The Lord of the Rings - with added jokes and songs - might just have a bizarre but brilliant logic.

The Legend of Rooney's Ring opened at the Royal Court theatre in Liverpool on Friday, and has its basis in a famous if not-necessarily-accurate myth from the couple's origin story.

In 2004, a tabloid newspaper claimed that Coleen had thrown her £25,000 engagement ring out of a car window at a red squirrel reserve after reports about Wayne's behaviour.

That attracted a flock of treasure hunters. "The next day everyone came out," says the play's writer Helen Serafinowicz, who's from Liverpool.

"The rumour had spread, and everyone was looking for it with their metal detectors and stuff. I've always just thought that was such a Liverpool story, whether it's true [or not]. I've heard lots of different versions of it."

Coleen addressed the incident in her 2007 autobiography, saying she and Wayne were "going through a rough patch" but that "you shouldn't always believe what you read".

Serafinowicz, one of the creators of hit sitcoms Motherland and Amandaland, saw comic value in merging the urban myth of Coleen's supposedly missing engagement band with JRR Tolkien's classic ring quest.

So she has written "a Game of Thrones-y, Lord of the Rings-type of medieval caper".

"What I wanted to avoid is targeting the Rooneys," she stresses. "They are an easy target, and I don't want this to be like dragging them through the mud, because that's easy and they've already had that.

"I mean, I just think they're great. I've always just thought Coleen was so cool and a great role model.

"So it's just a silly fantasy tale, loosely based on this ring."

In the show, the football legend is portrayed by Liverpool comedian John May. "I'm dressed like He-Man, let's put it that way," he says of Wayne's makeover to resemble the macho, scantily-clad, sword-wielding 1980s cartoon hero.

It's all deliberately over-the-top and tongue-in-cheek, but the cast insist any ridicule is entirely affectionate. The couple have arguably earned respect by surviving various highs and lows in the public eye, which began with intense press scrutiny when they were childhood sweethearts.

"They were only kids, and that wasn't on," adds May. "So it's created two really strong characters, because they've had to be.

Emma Grace Arends is playing Coleen on stage, and can hardly contain her excitement.

"I've listened to her autobiography about two or three times now. She's got the documentary on Disney. I've really done my research on her," the actress says.

"It just made me love her even more, and we all do. She's brilliant, she really is, and she's a true Scouser.

"But also, they aren't actually Wayne and Coleen in it. It is fantasy, it is Lord of the Rings."

The Legend of Rooney's Ring is typical of the homegrown comedies that come thick and fast at the Royal Court, which probably has a closer connection with its local crowd than any comparable theatre in the UK.

The venue aims to stage only original crowd-pleasing plays, often using sport-related stories to attract audiences in the football-mad city.

Recent shows have included Red or Dead, starring Peter Mullan as former Liverpool manager Bill Shankly; and Speedo Mick The Musical, about the Everton-supporting charity hero.

"That audience want to be entertained and they like things that are relevant to them," says executive producer Kevin Fearon.

"We focus on comedy and musical comedy. We focus on stories that relate to people in Liverpool, and we put characters on stage that relate to those people - people they could recognise, even if they are larger than life."

The theatre is making its mark beyond Liverpool, too - it staged the premiere of a stage adaptation of 1980s TV show Boys From the Blackstuff, which transferred to the National Theatre and West End.

Otherwise, old classics are out, though. "Our audience wants to see things they know on stage. So giving them an Ibsen or a Shakespeare or an Alan Bennett doesn't really work," Fearon says.

He really got the message when the venue revived Michael Frayn's 1982 farce Noises Off in 2014 – and he had to plead with a group of 10 women to stay for the second half.

"Ten minutes into act two, one of them stood up, then another, and then all of them stood up. One of them turned around and saw me at the back and gave me two fingers as they left the auditorium.

"They were watching a bunch of middle-class actors being daft, and that's not real enough for them.

"So our work has to connect with those people who will walk out, will go to the pub."

Lindzi Germain plays Queen Colette, Coleen's mum, in The Legend of Rooney's Ring, and has starred in many Royal Court shows. "We're not sitting you there for two hours being serious, taking you on a journey where you've got to think about something," she says.

"You haven't got to think of anything. Just sit down, have a drink, relax and have a laugh and escape for two hours."

The theatre's informal atmosphere is helped by having tables in the stalls where food is served. For many people, the venue has taken the place of social clubs that have shut down, Germain says.

"They come in at half six, get their tea, meet all their mates and watch two hours.

"Some people get absolutely hammered. Some people just have a few drinks, but also have a great night out and a laugh."

The Legend of Rooney's Ring is at the Liverpool Royal Court until 23 August