As Us exclusively revealed, Winslet secretly wed fellow Brit Ned Rocknroll -- the nephew of Virgin billionaire Richard Branson -- in early December of last year after about a year of dating. (Winslet's Titanic costar Leonardo DiCaprio walked her down the aisle.)
The baby-to-be will join older siblings Mia Threapleton, 12, and Joe Mendes, 9, the star's kids with ex-husbands Jim Threapleton and director Sam Mendes.
"I've really learned a great deal about myself, in the last four years in particular," the Mildred Pierce actress told Harper's Bazaar UK earlier this year. (After her highly-publicized split from American Beauty director Mendes in 2010, she rebounded with model Louis Dowler later that year, and then stepped out with Rocknroll in summer 2011; the pair both survived a devastating fire on Sir Richard Branson's private Necker Island.)
"I think I can see more clearly now – about how the pattern of past experiences has shaped who I am, and the characters I have played – and I'm grateful for that."