Laura Dern celebrated her son Ellery Walker Harper's 21st birthday over the weekend by sharing a sweet message and a rare photo of her two kids on social media.

The actress took to Instagram on Sunday, posting a sweet tribute to her eldest child, calling him the "greatest gift I could have ever dreamt up."

"Happiest 21st birthday to you my amazing son/friend/inspiration. You teach me every day...about art..empathy..and grace," Dern, 55, wrote. "You are a profound human and artist. And you are such a kind and amazing man. I'm so blessed and lucky to love you and learn from you. And you make me laugh every day."

The post featured a throwback photo of Harper as a little boy as well as a recent family snap of the actress, Harper, and Dern's daughter Jaya, 17, with Dern's mother Diane Ladd, 86.

Dern shares both children with ex-husband Ben Harper. The two were married from 2005 to 2013.

The Oscar winner also recently celebrated her father Bruce Dern on his 86th birthday, sharing a photo of him with her son.

"Happy birthday dad," she wrote in the caption. "Gorgeous to see you with your grandson and listen to your amazing stories."