He wrote: "Everyone has asked, not unsurprisingly, did Madonna say hi since I was backstage and the answer is no. Like Adele she decided it was a step to far." (sic)
With a single tweet, it has the power to reignite the old feud between the singers. It comes amid reports Madonna faces £300,000 fine during the world tour.
His latest bombshell sent shockwaves on social media with many of his followers responding to the showbiz gossip beneath his post.
— Boy George (@BoyGeorge) October 17, 2023
"It's their loss xx," one wrote, among the sea of comments.
"You really have to feel sorry for them. They probably don’t know what they’re missing."
"Too nervous to talk to an international star.” Others added. “Shame on her. That’s not right."
"They were too nervous to say hi to an icon!"
"She didn't want to be out shone!"
"She always was a material girl George."
Yahoo has reached out to Madonna and Adele’s representatives for further comment.
Boy George and Madonna's feud
Boy George has never shied away from controversy and has clashed with celebrities from all walks of showbiz, from Liam Payne to the late George Michael.
The star burst back onto our screens again when he starred on I'm A Celebrity... Get Me Out Of Here, clashing with some of the fellow campmates including Scarlette Douglas.
But arguably one of his biggest showbiz feuds has been with Madonna.
Reports of their feud goes way back to the 1990s — when George responded to Madonna's 1991 Vanity Fair cover saying: "Comparing Madonna with Marilyn Monroe is like comparing Raquel Welch with the back of a bus."
In 2006, he reportedly said the singing superstar was a "vile, hideous human being with no redeeming qualities".
These words were then repeated on The Jonathan Ross show in 2021, provoking a surprising response from George.
Looking back on the past, he then told the Jonathan Ross Show in 2021: "It's not something I would say now… it's really just, I'm actually a bit embarrassed I said that."
He added: "I treat Boy George from the 80s as a sort of cartoon character... I'm going to drop 60 songs for my 60th birthday."
Of Madonna, he said: "Madonna… she fascinates me. I love Madonna. Come on, how can you not? Of course I do. She's my contemporary. I've actually just sold some paintings of Madonna that I did."
Over the years, Boy George has addressed the comments and at one point even called them "awful" remarks.
In 2014, he told The Huff Post: "I've said awful things about Madonna and I’m not proud of that at all — I’m really not proud of that because I didn’t know her."
Read more: Madonna
Madonna ‘facing £300,000 fine after breaching super-strict show curfew’ (Bang showbiz, 2-min read)
Watch Richard Madeley questions I'm A Celebrity's handling of Boy George