It has been a varied 20 years for Optimo.

There was the fake wedding held at their club night for example, or the time they paid homage to classic films like 2001: A Space Odyssey and Apocalypse Now.

Then there was the trip to China where they confused the authorities.

Throughout it all, whether at their famed Sunday night Sub Club residency that became a Glasgow clubbing institution or trips around the world, life was never dull.

Now the pair – Keith ‘JD Twitch’ McIvor and Jonnie ‘JG’ Wilkes - will mark two decades together with a special all-dayer at the Galvanizers Yard at SWG3 this Sunday, with a bill featuring top talent from across the world.

“I can still clearly remember the first Sunday night when we started it,” says Keith.

“We had very low expectations and people didn’t traditionally go out on a Sunday night, so we had no aims for it beyond it being a low-key night. Then suddenly it exploded. Even then, I remember thinking it was a short lived little fad, but it kept going and gaining momentum.”

The reasons for the club’s growth in popularity can be traced to the duo’s ability to mix every genre under the sun, as well as their commitment to having fun. That is where the likes of their film night themes crept in, as Keith recalls.

“Both Jonnie and I are serious music freaks but we’ve always thought that a night out should be fun,” says Keith.

“You should leave it with a smile on your face, or a memory of something crazy happening. We’re big film fans, so one week we tried to turn the club into the set of 2001: A Space Odyssey on absolutely zero budget, and failed miserably.

“Later on we did the same with Apocalypse Now, although we had more money then. So we got pyrotechnics people to let smoke bombs off and got vegetation in from Glasgow parks department to make the club into a jungle.”

It earned them a devoted following, to the extent that a couple of their friends who’d met in the club and ended up getting married thought it’d be a great idea to celebrate the wedding there.

“They’d got married for real the day before,” explains Keith.

“Then at the club one of their friends was dressed as a minister and they had this mock ceremony, much to the confusion of some of the people in the club who thought there was a real wedding going on.”

All good things must come to an end though, and in 2010 the twosome pulled the plug on their Sunday night spot, partly due to international demands and partly due to a feeling that the residency was becoming too much like a job.

The prospect of a 20th anniversary celebration back home was far too tempting, especially as Keith points to Glasgow as being key to Optimo’s success and longevi

“We wanted to celebrate 20 years in the city that made us,” adds Keith, who stays in the West End.

“Everyone on the line-up is someone we had a close relationship with or we’ve seen in the past couple of years and thought they’d be great to bring to Glasgow.”

The event, which features a host of acts including Black Madonna, Errorsmith and Happy Meals will also benefit local foodbanks and Glasgow’s Coalition For Racial Equality & Rights. That’s not a surprise, as Optimo regularly try and raise funds for good causes.

“It’s disgusting that one of the richest countries in the world still has so many people reliant on foodbanks,” says Keith.

“It’s important to us that Optimo is part of the community and helps with local issues, so it was important to attach that to the festival as well.”

Whatever happens on Sunday, it’s unlikely to be as strange as the duo’s trip to China.

“Before we played there we had to submit the setlist for what we would play, which as a DJ is ridiculous because you never know what you’ll play next,” chuckles Keith.

“So we just presented this random list of what we might play, and then we got there we found these two guys standing there with checkboards, and they’d tick them off one by one. Thankfully the songs were so obscure that I’m pretty sure they had no idea what we were doing, but I did worry that at one point the set would be halted by someone going ‘this song is not on the list…’”

Optimo 20, Galvanizers Yard, Sunday, at SWG3, £40, 2pm

Jonathan Geddes