Kate Hudson and Matt Bellamy recently confirmed their split up, but not many people know that they have called off their engagement some time ago. They will be sharing custody of their 3-year old son Bingham Hawn Bellamy.

Hudson's rep confirmed the break up news to People last Monday, "Kate and Matt have been separated for some time now." Her rep added, "Despite this, they remain very close friends and committed co-parents."

The 35-year old actress and the 36-year old rockstar got engaged in 2011 after their son was born, but they never set a date for their wedding. During an interview with Women's Health, the star of "Bride Wars" revealed what marriage is for her.

Kate said, "My parents aren't married. And one of the reasons why they never got married is because they had been married before and they liked it the way it was. They didn't feel like they needed a piece of paper to be committed."

That clearly showed that the actress isn't the marrying type, but what could be the real reason for Kate Hudson and Matt Bellamy's split up? There are rumors that there's a third party involved and his name is Derek Hough.

The "Almost Famous" star was seen making out with the "Dancing with the Stars" pro in public and that's just a few days after the news broke about her split up with the Muse frontman. The two met when Kate joined the dance-off and they quickly got intimate.

According to Us magazine, the couple didn't care who was looking after they arrived at a restaurant called Nice Guy in Los Angeles. A witness told the magazine, "They were totally kissing." The insider added, "So scandalous!"

When Mail Online caught up with the 29-year old dancer, he was asked if he was the reason behind Kate Hudson and Matt Bellamy's split up. Derek Hough didn't deny the romance, but instead remained tightlipped about it. He said, "It's not really the time or the place to talk about it buddy."