The 38-year-old English actress, who welcomed baby boy Bear on Dec. 7, graces the cover of the February 2014 issue of Glamour UK. The blond beauty, who looks chic in a gray wool jacket, opens up the magazine about the newest addition to her family.
"We haven't ever really had that conversation; it was always going to have my name," the Oscar winner reveals matter-of-factly. Rocknroll was born Abel Smith but had his name legally changed.
Winslet is already mom to Mia, 13, with first husband Jim Threapleton, and Joe, 10, with ex-hubby Sam Mendes. Her two older children have their father's last names.
"Mia and Joe have it as part of their name, so it would be weird if this baby didn't," she adds. "Of course we're not going to call it RocknRoll."