Bros' Matt Goss likes to flash his penis to his twin brother Luke on FaceTime.
Matt and Luke Goss in 2009
The lead singer enjoys winding his sibling up and thinks it's funny to whip his willy out while they're video messaging because nine times out of ten he's with someone.
Speaking on Heart FM, Luke said: "We have a FaceTime at least four times a day. I'm not going to go in to details but Matt has a game which is very disturbing."
When pushed on what he tends to reveal, he said: "Undercarriage."
Hosts Jamie Theakston and Amanda Holden looked shocked, to which Luke added: "Seeing your reaction to this is almost like therapy to me. I feel the same way as you. Now he's traumatising us all."
Matt explained: "Seeing your faces makes me feel extremely happy."
Asked what fans should do if they ever get a FaceTime call from Matt, Luke said: "Open it cautiously."
Meanwhile, Matt, 50 - who previously appeared alongside his bandmate and twin Luke in 'Bros: After the Screaming Stops' - loves being perceived as "eccentric."
He said recently" "I hear it all the time, especially since the film, but I'd rather be eccentric than not. I really do enjoy walking the streets and being around people who know our history. People come up and converse like they've known me for years. I'll get into a black cab and the driver will immediately go, 'How's your brother? How's Vegas going?' without even saying hello first! I like it that way."
He also claimed that having a twin is incomparable to any other type of relationship.
He explained: "You understand each other better than anyone in the world. It's annoying and can be a hindrance but it's also the reason why, when we're in a room together, something magical happens. Luke's been staying with me in Vegas while we rehearse and we've been mucking around together, just being brothers.
"We played Marco Polo in the pool the other day for the first time in decades, which was hilarious. Luke came along to my show that night and was sitting in the front row, still shouting 'Marco!' I was like 'F**k off, I'm busy!'"