Kate Hudson and Matt Bellamy unveiled the first photo of their new baby boy, Bingham, over the weekend.
"Family life!" wrote Bellamy on his Twitter, attaching a photo showing his glowing fiancé and their new baby.
Bingham "Bing" Hawn Bellamy was born in Los Angeles just over five weeks ago.
Hudson and Bellamy, who is the front man for the British band Muse, were first linked in 2010. In January 2011, the couple confirmed that they were expecting their first child.
Four months later, Hudson, 32, announced their engagement on the Today Show.
"He's a beautiful man and I'm very excited," she told Matt Lauer of Bellamy.
Hudson first rose to fame in 2001 for her role as Penny Lane in Cameron Crowe's "Almost Famous." She has since made several romantic comedies, including "How to Lose a Guy in 10 Days," "Bride Wars" and her latest, "Something Borrowed," based on the best-selling novel of the same name.
She has a son, Ryder, from a previous marriage to Chris Robinson, also a musician. Hudson also had a brief relationship with New York Yankees player Alex Rodriguez in 2009.
Bellamy and his band Muse have sold more than 10 million albums worldwide, with hits including "Starlight," "Uprising" and "Resistance." Muse co-headlined this year's Lollapalooza music festival in Chicago with Eminem and Coldplay. Bellamy is expected to return to the studio with his band in September to work on their sixth studio album.