Sherlock star Mark Gatiss directs husband Ian Hallard's heartfelt comedy The Way Old Friends Do at Park Theatre.

Hallard also stars as one of a duo of old schoolfriends who reunite in midddle age to form the world's first drag ABBA tribute band. But their friendship is tested by a life on the road full of platform boots, fake beards, and an attractive stranger.

The Islington couple previously appeared together at the Finsbury Park venue in The Boys in the Band, and now collaborate on Hallard's debut play which arrives in north London on March 15 after opening in Birmingham. Ham & High: Ian Hallard in rehearsal for The Way Old Friends DoIan Hallard in rehearsal for The Way Old Friends Do (Image: Simon J Webb)

Hallard says writing his first play was motivated by "what I myself wanted to be in".

"I thought, 'Well, if it's the first thing I write, I'm going to write a part for myself. What would I be most excited about if my agent rang tomorrow? It would be an offer to play Agnetha from ABBA.' Then I had to reverse engineer things and construct a storyline in which that could happen.

"When I told my friends, they got excited because they thought I was actually setting up a drag ABBA tribute band. I did extensive Googling to see if such a thing already existed, and as far as I'm aware, it doesn't."

Gatiss, whose stage and screen work ranges from The League of Gentlemen to co-writing and appearing in Sherlock, said when he first read it he found it "very touching, very funny, very true."

"It's the sort of play people need right now. It's extremely celebratory, it's about friendship, about love, about fun. It’s also about time and how it changes us."Ham & High: Married couple Ian Hallard and Mark Gatiss live in Islington and have previously acted together at Park TheatreMarried couple Ian Hallard and Mark Gatiss live in Islington and have previously acted together at Park Theatre (Image: PA)

Hallard says it's autobiographical only in that: "It's about a gay, middle-aged man from Birmingham who is a massive ABBA fan."

"A chance meeting via a gay dating app means he ends up running into the kid he was great friends with at school but lost touch with. I was interested in exploring friendship, as opposed to a romantic relationship between these two middle-aged, queer men. With The Way Old Friends Do, I had a ready-made title from ABBA's back catalogue, and knew early on that the final scene would revolve around that song."

Of working together Gatiss jokes that he hopes they don't go the same way as the couples in ABBA: "A lot of couples never work together because they'd rather leave it at the door, but so far so good! It's about having a shorthand, in rehearsal as a scene is unfolding, I know what Ian will be wanting to say to me. Also, we can compare notes at the end of the evening without having to organise a special session!"

Hallard adds: "We've doneit a few times but this is a different dynamic because we haven't worked together as director and writer, so watch this space. But given past experiences, I have no cause for concern!"

Ham & High: Mark Gatiss in rehearsal as director of The Way Old Friends Do Mark Gatiss in rehearsal as director of The Way Old Friends Do (Image: Simon J Webb)

Happily the play has the blessing of the ABBA estate: "I would have been devastated to be slapped down by my heroes," says Hallard whose mother was pregnant with him when the band won Eurovision in 1974.

"It’s been a lifetime of devotion for me. The play speaks about being a fan We're all a fan of something. That level of devotion and ownership is universal.

"It's a backstage play, in the vein of The Full Monty or Stepping Out: a bunch of plucky amateurs deciding to put on a show. Although ABBA is very much the setting, and part of the show, it's not a play about ABBA, it'sabout being an ABBA fan."

Luckily Gatiss also appreciates the Swedish hitmakers: "They’re loved because they're just so bloody good. They have an astonishing range of hits, styles and genres. They're both gloomy Swedes and insanely infectious disco-mongers."

He adds of the play: "It's moving and joyous. Like ABBA, it's bittersweet, but ultimately upbeat, and a joy to be around."

The Way Old Friends Do runs at Park Theatre from March 15 until April 15.