Michael J. Fox, Tracy Pollan celebrate twin daughters Aquinnah and Schuyler turning 28

Michael J. Fox and Tracy Pollan are celebrating their twin daughters Aquinnah Fox and Schuyler Fox for their 28th birthday.

The "Back to the Future" actor and the "Family Ties" alum each took to Instagram to mark the special day.

"Weeeeeeeeeeee! Happy Birthday Aquinnah and Schuyler, you guys live your best lives X 2! Love, Dood," Fox captioned his post, which featured three more recent photos of himself with the twins.

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Pollan also shared photos of Aquinnah Fox and Schuyler Fox in recent years, but her post also included some throwback photos of them from when they were kids.

"Happy birthday to these two beautiful humans!" she wrote alongside the post. "I could not love you more and I hope you have a fantabulous day!"

Fox and Pollan, who married in July 1988, are also parents to son Sam Fox, 33, and daughter Esmé Fox, 21.