Time flies when you're adorable it seems! Lucy Liu took to Instagram on Sunday, Aug. 27, to wish her baby son, Rockwell, a happy birthday — and we can't believe he's two years old already!

"Happy 2nd birthday to my darling Rockwell. You are my rainbow every day," she wrote alongside a photo of him with a lit candle. He's so grown up today!

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Lucy welcomed little Rockwell via surrogate as a single mom back in August 2015. At the time she announced on Instagram, "Introducing the new little man in my life, my son Rockwell Lloyd Liu. In [love]!" with a photo of herself holding the then-newborn.

The front side snap was a treat for Lucy fans, as the actress rarely shows her son's face in photos. She often shares cute pics of the two on her social media accounts, however, we never get to see what Rockwell really looks like. She's recently shared cute snaps of the two at the museum and the zoo, both in NYC where the mother and boy reside.

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She gave a similar shout-out to her little man on his first birthday last year. "Happy 1st birthday to my little love Rockwell! This has been the most incredible year of new adventures and endless fun. Giant thanks for everyone's generosity," she wrote at the time.

In a previous exclusive interview with Closer Weekly, Lucy opened up about the possibility of Baby No. 2. "I don’t know. For me, it’s just about the present moment," she said. "So I’d like to just enjoy before I start to [look into the future] about anything else. Because I think sometimes it can get too overwhelming and then you’re like, 'Oh my god!' Because you don’t really get to be where you are, you’re just too busy planning for the next thing." Here's hoping Rockwell gets another cute little sibling sooner rather than later!