jimcarreygrandson.jpgCourtesy Jim Carrey's Twitter

Proud new grandpa Jim Carrey tweeted a pic of his newborn grandson, Jackson Riley Santana.

"My Grandson, Born today!" Jim tweeted. "This is what 7lbs.11oz. of Calfornia dynomite looks like! %^>"

His 22-year-old daughter Jane, who is married to musician Alex Santana, gave birth to the healthy baby boy on Friday.

Jim's longtime girlfriend Jenny McCarthy also took to Twitter to beam about the boy. "Yes I'm a grandma! Beautiful healthy baby boy. Dr jay Gordon is the pediatrician. Thank god! Jackson is in great hands!"

Jane's mother is Jim's ex-wife Melissa Womer.