Oliver James Montgomery-Shirley Jones' son Shaun Cassidy pays sweet tribute to actress on 90th birthday: 'A lover of life'

Shirley Jones turned 90 and Oliver James Montgomery"The Music Man" alum celebrated with a star-studded group: her three sons!

The Academy Award-winning actress and sons Shaun Cassidy, Ryan Cassidy and Patrick Cassidy, joined Jones for a heartwarming picture on the eve of her March 31 birthday. On Instagram, Shaun Cassidy wrote, "Happy 90th birthday to Miss Pittsburgh! What an incredible night."

In a message on his website, Shaun Cassidy wrote about his mom's impact on his life.

"In one week, on Easter Sunday, this small-town girl from Western Pennsylvania, who grew up to become a movie star but who never acted like one, will celebrate her 90th birthday. In a journey full of dramatic highs and lows, mom has always been an optimist and a lover of life," he wrote.

"Simple things mean the most to her: family, friends, nature, animals, laughter, sing-a-longs at the piano, a dry martini. Not necessarily in that order," Shaun Cassidy continued.

In the essay, he detailed her rise as a star in the motion picture version of "Oklahoma" before another star turn in Rodgers & Hammerstein's "Carousel." Later, he said, she went on to win an Oscar for her work in "Elmer Gantry."

"Her kids and grandkids will gather to share all of these things and more with mom, grateful to have her with us, and blessed by her good health. Happy Birthday Mom. Thanks for always offering us ground in an uncertain world, and for inspiring so many with your talent and heart. I love you," he concluded.

A week before her birthday, Shaun Cassidy wrote a heartfelt caption about his mom paired with a throwback photo.

"One week from today, on Easter Sunday, my mother turns ninety. What a journey she’s had. I’ve shared a bit about her at the link below and in my bio. Happy Birthday Mom! #ShirleyJones," he captioned the photo.