Early last year, the Lighthouse singer stopped by the South African compound with DJ and producer Jax Jones to perform their track Whistle.
Contestants like Kai Fagan, Sanam Harrinanan, Lana Jenkins and Tanya Manhenga danced the night away as the celeb duo put on a lively and intimate show.
Reflecting on the experience now that the All Stars series is in full swing in the same location, Calum told The Sun: “Absolutely mad. I mean, it’s like Big Brother, basically over in South Africa with a lot of really fit people. I’m not a huge Love Island watcher. Some of my mates were just like ‘Oh, my God! I can’t believe you’re over there! And did you speak to them’ and all this kind of stuff.
“We couldn’t, because they were in a Covid bubble when we went, so we couldn’t engage with the guys. The first time that I got to see them is when I came out and performed, and then we had a quick selfie with them and I had to get straight back out again. So it was a bit of a weird, surreal experience. It was just like they put me in the belly of the beast and then pulled me back out again.”
Calum and Jax couldn’t resist getting up to a bit of mischief during their whistle-stop visit.
“What was quite funny was whilst all the guys were in the garden,
me and Jax was just doing some like slow-mo walking into the house,” said Calum.
“Me and Jax snuck away from the team and just went around the house, and were just looking and taking pictures like in the bedrooms and dressing room where they get ready thinking that we were like super sneaky not realising that they have multiple cameras in every single room.
“The production team was like ‘you’re going to have to delete all of that off your phone’ [laughs]. Sorry’. But it was an amazing experience.”
It’s just another in a long list of memorable moments when it comes to Calum’s impressive career.
Almost 10 years into his life in the limelight, he is still going from strength to strength.
Last year he was handpicked by Ed Sheeran to support him on the Asian and European legs of his world tour.
The first sold out show took place earlier this month in front of 44,000 people in Dubai.
Calum said: “It’s absolutely mental. But, like I said, I’m counting my lucky stars. I’m literally pinching myself every morning… I remember being at Asda and I was what my mum called the ‘trolley dolly’, where I was responsible for collecting shopping trolleys from the bays and putting them back in the shop.
“And now I’m out in Asia supporting Ed Sheeran. I’m just like ‘what is that?’ I pride myself on being the same guy that was pushing those shopping trolleys around but with much shorter hair. I pride myself on being the same guy. I’d like to think that that’s true.”
Calum built a relationship with Ed in 2016 when he was supporting the superstar’s pal Jamie Lawson.
A few years later they worked on a track with French DJ and producer David Guetta and connected over family life and music.
Then just months ago Ed announced Calum would be joining him on his huge European and Asian tour, leaving him stunned.
He said: “To be supporting him around the world is just like a dream come true. I mean, what better mentor to kind of have on the road, and to just learn from and soak up all that energy and work ethos. He is a mega star. I’m just on honoured. Pinching myself.”