The actor posted a rare picture on his Instagram Stories of a young Sosie playing with a puppy as she innocently just stared at the camera.
WATCH: Kevin Bacon and Kyra Sedgwick perform adorable duet for wedding anniversary
The photograph marked a touching celebration for Sosie's milestone 30th birthday, as Kevin wrote: "Happy 30 to this gem. The girl not the dog."
She marked the occasion herself by posting a picture while eating a pizza with open lunch boxes behind her, writing: "Thirty flirty and thriving."
Sosie has had a successful career in the entertainment industry just like her parents, having followed in their footsteps and become an accomplished actress.
Kevin shared an adorable childhood picture of his daughter on her birthday
Kevin and Kyra are also parents to son Travis, three years older than Sosie, who is also an entertainer, the singer in the band Contracult Collective and guitarist for black metal band, Black Anvil.
And while the celebrity couple are more than supportive of their children's careers, they were initially worried about how their children would cope in the notoriously cut-throat environment.
Kevin suffered a very public breakdown during a slump in his own career and he didn't want his children to suffer that.
The Footloose star told The Telegraph in 2013: "You're only as happy as your least happy child. We were only thinking about the struggle. "And you want your children to live a life with as little struggle as possible. You never want bad things to happen. But of course, that's just not possible."
The celebrity couple are parents to Sosie and son Travis
Kyra is in agreement and said in a previous interview: "Honestly, I really just want them to be happy. It is difficult being in this business, knowing how hard it is even when you're successful. The hurt, the rejection, the insecurity of thinking you're never going to work again... I don't want that for my kids."
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