Gwen Stefani's soon-to-be ex-husband Gavin Rossdale was reportedly once involved in a "raunchy sexual relationship with Boy George."

According to Radar Online, the Bush front man and the Culture Club icon were involved in a fling, before he ever settled down with Stefani. She and Rossadale are now involved in a messy split that was brought on by recent rumors of his affair with the family's nanny.

News of Rossdale's dalliance with Boy George comes courtesy of the "Do You Really Want to Hurt Me" singer's close friend Sham Ibrahim.

"I worked on the 'Hey Baby' music video with Gwen and when Gavin came on set, I realized that it was the same guy that used to run around with Marilyn and Boy George in New York City," Ibrahim said. "I used to run in that circle. This was before Gavin got famous."

Radar previously reported Rossdale came clean about his sexual affair with cross-dresser Marilyn in 2010.

"Marilyn and Boy George used to hate each other," Ibrahim added. "Boy George always hated Marilyn because he was so pretty and Marilyn always hated Boy George because he was so famous."

By Ibrahim's recollection, Rossdale and Marilyn were in love and openly an item. He added the two would often go places hand-in-hand and would freely cuddle up.

Word is, when Rossdale met Boy George, he instantly "traded up," ditching Marilyn.

"Gavin was running all around NYC bragging about his relationship with Boy George and having sex with him," he said. "But after Boy George found out that Gavin was spreading his business all over town, he cut him off."

Meanwhile, Stefani and Rossdale started dating in 1995 and were married seven years later. Stefani officially filed for divorce in early August, citing irreconcilable differences.

The couple has three young children together, and sources indicate they do not have a prenup agreement. The 45-year-old Stefani is estimated to have a net worth of around $80 million, while the 49-year-old Rossdale is rumored to be worth roughly half of that amount.

Stefani is now dating fellow "The Voice" judge Blake Shelton.