Estevez, 28, who is Sheen's daughter with high school sweetheart Paula Speert, gave birth to a baby girl named Luna. "It's impossibly a most wondrous day," Sheen, 47, told TMZ of becoming a grandfather. "My bucket list is a thimble!"
Sheen confirmed his daughter was expecting her first child during an appearance on The Late Show With David Letterman in January. "Me as a grandfather, Dave . . . I don't know. It's like the world's going to crack in half," he joked. "It's fabulous. It's just not a title I'm ready to adopt."
Sheen is also dad to daughters Sam, 9, and Lola, 7, with second wife Denise Richards, and 4-year-old twin sons, Bob and Max, with third wife Brooke Mueller. When Letterman asked the actor if he thought he'd be a good grandpa, Sheen quipped, "Well, yeah, because you can leave the kid!"
This article originally appeared on Usmagazine.com: Charlie Sheen Is a Grandpa! Cassandra Estevez Gives Birth to Baby Girl Luna