Bruce Willis celebrated his first Father's Day as a grandfather.

His daughter Rumer Willis, a new mom to baby girl Louetta Isley, took to Instagram to share a few photos of the action star with his new granddaughter.

She captioned it, "Fathers to the old and new. Seeing my father hold my daughter today was something I will treasure for the rest of my life. His sweetness and love for her was so pure and beautiful."

"Papa I'm so lucky to have you and so is Lou," her message continued. "Thank you for being the silliest, most loving, coolest Daddio a girl could ask for. Best Girl Dad in the game...."

Willis also congratulated her partner Derek Richard Thomas on his first Father's Day, writing, "@derekrichardthomas Happy 1st Father's Day. Thank you for building a beautiful garden for Lou to play in and eat from."

Emma Heming Willis, Bruce's wife, paid tribute him on Father's Day as well.

"What he's teaching them will span generations," Heming shared with a photo of their daughters. "Unconditional love, kindness, strength, compassion, patience, generosity, resilience."