The baby boy, whose name is yet revealed, is the second child of the actress and the first one for the Muse star.
Kate Hudson and fiance Matthew Bellamy are now parents to a "healthy baby boy". The actress gave birth to their first child together on Saturday, July 9 night in Los Angeles, her rep has confirmed to People.
Hudson previously said that she had a hunch that the baby is a girl, perhaps because she has had a son with former husband Chris Robinson. "It feels like a girl, but I don't know. Ryder thinks it's a girl," she said back in January, referring to her 7-year-old son.
Hudson announced her pregnancy in January this year and she got engaged to him three months later after a year of dating. "He's lovely," Hudson told Elle U.K. back in September. Speaking of the then-impending second child, Hudson said with a laugh, "This is a totally different pregnancy, completely. It couldn't be more opposite...With Ryder, I didn't even have a nursery. I didn't really have a house until I was seven months pregnant."