Liev Schreiber Pens Sweet Message on Son Kai's Birthday!

Liev Schreiber is celebrating his son Kai‘s birthday!

The 53-year-old Ray Donovan actor took to Instagram on Sunday (December 13) to share a sweet message on his son’s 12th birthday.

PHOTOS: Check out the latest pics of Liev Schreiber

“Happy Birthday Kai!!! I love you beyond beyond,” Liev wrote along with a photo of Kai posing with balloons.

Naomi Watts, Kai‘s mom and Liev‘s ex, also took to Instagram to celebrate Kai‘s birthday.

“Happy Birthday to Kai!! Your beautiful spirit, wicked humor and quick mind inspire us all. I feel so lucky to be your mummy. Every day you blow me away. The depth of your thinking is truly special, you are my angel 😊😊😊,” the 52-year-old actress wrote along with a bunch of photos.

Liev and Naomi also share 13-year-old son Sasha.

Also pictured inside: Liev Schreiber arriving in Venice, Italy on Saturday (December 12) to film his new movie Across the River and Into The Trees.