Lucy Liu welcomed son Rockwell via gestational surrogacy in 2015

Lucy Liu celebrates son's birthday
Credit: Lucy Liu/Instagram

Happy birthday, Rockwell!

Lucy Liu’s son turned 5 on Friday, and the actress marked the occasion with a sweet Instagram post featuring a rare photo of the mother-son pair together.

“My darling son turned 5 yesterday,” the actress, 51, wrote alongside a shot of Rockwell blowing out his candles, while Liu stands by in a festive party hat. “He is a rainbow of light and his energy is pure magic.”

Liu also took the opportunity to show support for presidential hopeful Joe Biden and his running mate, California Sen. Kamala Harris, who will face President Donald Trump and Vice President Mike Pence in the upcoming Nov. 3 election.

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“As a human being, a woman, a mother, a daughter - now more than ever we must come together to fight for the soul of this nation,” the Elementary star wrote. “Let’s all wish as hard as he is for a brighter and safer future for our children and Mother Earth. I am all in for #BidenHarris2020 and their vision for an inclusive America @JoeBiden @KamalaHarris.”

Liu welcomed Rockwell via gestational surrogacy in 2015. Several months after his birth, the star reflected on her decision to turn to surrogacy.

Robin Marchant/Getty

“It just seemed like the right option for me because I was working and I didn’t know when I was going to be able to stop,” Liu told PEOPLE at the time. “I decided that was probably the best solution for me, and it turned out to be great.”

“I didn’t realize how quickly babies progress,” she added of Rockwell, who was 8 months old at the time. “Very basic things that you just take for granted. They’re just this little lump of flesh, and then all the sudden they’re turning around, they’re observing you and they’re smiling and they’re interacting. It’s a magical experience.”