Cameron Douglas posted a sweet tribute to his pregnant girlfriend
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Cameron Douglas can’t wait to be a dad!

The son of Michael Douglas took to Instagram Friday to post a loving tribute to his girlfriend Viviane Thibes, which showcased her growing baby bump.

“So it would be an angel was in the making,” Douglas, 38, wrote. “From high above this Soul perched to determine just where her efforts were partaking.”

“Once decided this moonlight blazed without resistance; No longer just musings,” he continued.

PEOPLE confirmed the two were expecting in early August.

“Everyone is thrilled for him,” a source said, adding, “Michael is looking forward to being a grandfather.”

Cameron and Thibes — a 39-year-old yoga instructor originally from Sao Paulo, Brazil — were first spotted together in August 2016, when they were photographed walking hand-in-hand through New York City.

In addition to her practice and certification in Jivamukti yoga, Thibes is an actress, having received a bachelor’s degree in film at Hunter College in N.Y.C. and starring in a 2008 Brazilian film titled La riña.

The baby news comes a little over a year after Cameron was released from prison after almost seven years. He received a five-year sentence for possession of heroin and selling methamphetamine, and a subsequent sentence extension after he confessed to smuggling drugs into prison.

“Cameron is fine. He has not relapsed,” Cameron’s lawyer Benjamin Brafman told PEOPLE in June after Cameron tested positive for having marijuana in his system while on probation in April and May.

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In a 2013 essay he wrote from prison for The Huffington Post, Douglas said, “I feel thoroughly blessed. I have a beautiful and loving family who has faithfully supported me every step of the way, believing in me and refusing to give up in the face of one bleak adversity after the next.”

In July, Michael, 72, and Cameron were spotted out and about together in L.A., with the latter in town to visit his 100-year-old grandfather Kirk after getting permission to travel out of New York during his May court appearance.

The baby on the way will be Michael’s first grandchild. He is married to Catherine Zeta-Jones and the couple are parents to son Dylan, 17, and daughter Carys, 14.