New role for Charlie Sheen: He's going to be a grandfather

"Grandpa, tell me about your younger days." If Charlie Sheen's grandchild asks that question, he or she is likely to get some interesting answers.

Sheen's ex-wife, Denise Richards, made the announcement on Twitter: "I guess some of you have heard...@charliesheen is going to be a Grampa...yes GRAMPA! His beautiful daughter Cassandra is gonna be a mama..."

28-year-old Cassandra Estevez was married several years ago and is the daughter of Sheen and his high school girlfriend, Paula Profit.

Sheen also has four other children -- two daughters with Richards and twin sons with Brooke Mueller.

It's been nearly two years since Sheen's public meltdown, which led to him being fired from the hit TV show, "Two and a Half Men." He then took his rants on the road for a series of performances, filled with stories about drug-induced sex and parties.

Charlie Sheen has not yet publicly commented on his daughter's pregnancy.