VIDEO : Actress Mamie Gummer Welcomes Baby Boy

EXTRA reports that Meryl Streep has stepped into a new role as a Grandmother! Streep's daughter, 35-year-old actress Mamie Gummer, has recently given birth to a baby boy. This is Gummer and fiancé Mehar Sethi's first child. News of Mamie?s pregnancy was announced in December, a few months after Mehar proposed. Gummer is best known for her roles in ?True Detective,? ?The Good Wife? and ?Ricki and the Flash.? No word yet on the baby's name.