"We may not be a conventional family but we have love and humour and respect and care and I am proud to have walked this far with both of you and to have @lily_beckinsale walk us into the future," Beckinsale captioned a black-and-white video of herself and Sheen walking alongside their graduate.
"God bless love, and good hearts, and loyalty and friendship, and may we all have more and more of it and make more and more of it in the world ❤️," she added.
Beckinsale also shared a cute pic of Lily, 18, in her cap and gown as she graduated from Harvard-Westlake in Studio City, California.
"PHRESH out of high school @lily_beckinsale," she wrote alongside the snap. "I am so proud of you I have nearly forgiven you for saying other parents don't bring air horns to the ceremony that was a LIE ❤️❤️❤️❤️❤️go git it my brilliant gorgeous girl."