July 08, 2016 12:10 PM

Source: Valerie Pitalo/Instagram

Caitlyn Jenner just added one more grandchild to her family!

The I Am Cait star’s eldest son Burt recently welcomed a baby boy with his longtime girlfriend Valerie Pitalo.

Burt, 37, took to Instagram to announce the news Thursday, sharing two adorable pictures of his newborn son.

“She did it!” he captioned the first image, a sweet photo of Pitalo holding their baby boy.

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The proud father also shared a photo of their son nuzzling into Mom’s chest, sleeping soundly.

“So far so easy… Only 17 years 364 days to!” he quipped.

Burt, a race car driver, announced he was expecting a boy with Pitalo in December.

“I promised to wait until we had the ‘all healthy’ update, and we got it yesterday… My lil boy, just chillin… So happy I can’t see straight, he can’t get here fast enough,” he captioned an Instagram photo of an ultrasound.

Burt is Caitlyn’s first child with his first ex-wife Chrystie Scott, whom Caitlyn (at the time known as Bruce) was married to from 1972-81.

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The new father has been a staunch supporter of Caitlyn, 66, since she went public with her transition last year.

“I’m very excited. Part of me was screaming to say, ‘Hey, I’ve known for 25 years and I’ve always been supportive!’ I always will be,” Burt told Esquire in October. “I’ve always tried to be an outspoken supporter of the LGBT community.”

— Aurelie Corinthios

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