hudson042811_01_boy2.jpgKate Hudson and fiance Matt Bellamy welcomed a "healthy baby boy" to their family Saturday night, according to Kate's publicist. The couple has not yet made public the name of their new bundle of joy.

Hudson has a 7-year-old, Ryder, with ex-husband Chris Robinson of the Black Crowes.

Kate confirmed her pregnancy in late January and announced her engagement to Bellamy, frontman of alt-rock group Muse, on the Today Show April 27.

The pair are expected to retreat to Bellamy's London home where he'll record a new album. But they may wait a couple weeks at least -- it is believed Hudson gave birth at a Santa Monica-area hospital last night so she may want the little one to have a few weeks under his belt before they all hop on a plane!