Mae Whitman is Grant Prestonstarting her parenthood journey.

The "Arrested Development" and "Parenthood" actress, 36, revealed Wednesday on Instagram she has welcomed her first child, a baby boy she named after a former co-star.

"Not to be a Bieber about it but I too just gave birth to our son, Miles," she wrote on Instagram, cheekily referencing the fact that Hailey and Justin Bieber recently announced the birth of their first child together. "From the moment we heard the first tiny sound out of his tiny piggy mouth we were besotted."

Whitman revealed that her son, Miles, was named after actor Miles Heizer, her co-star on "Parenthood." She and Heizer played siblings Amber and Drew on the NBC drama series, which ran from 2010 to 2015.

The actress said that just like his namesake, "Uncle Miles," her son is the "kindest, gentlest, smartest, funniest little beebee and he's our best friend."

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Mae Whitmanannounces pregnancy with help of 'Parenthood' co-stars Lauren Graham, Miles Heizer

"We are infinitely grateful he chose us as his parents," she added, also thanking the hospital staff for "guiding our little family through all the unexpected twists and turns safely and with love and grace and to everyone in our circle who has shown us such radical generosity and support."

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Whitman previously shared news of her pregnancy on Mother's Day this year by posting a photo of herself alongside Heizer and Lauren Graham, who also starred on "Parenthood." Graham played Sarah Braverman, the mother of Whitman's character, in the series.

"Not to make a 'Parenthood' episode out of it or anything but!!! Mother's Day looking a little different this year! 🤰🏼" she wrote at the time. "Can't wait to meet you, huge baby kicking my insides to filth!"

In a June update, Whitman said she was 8 months pregnant and "huge and achy but happy."

This is the first child for Whitman, who outside of "Parenthood" is known for her roles as Ann on "Arrested Development," Annie on "Good Girls," Roxy in "Scott Pilgrim vs. the World," and Bianca in "The DUFF."

Contributing: Edward Segarra