Ben is Travolta's youngest child with late wife Kelly Preston, who died in July after a battle with breast cancer. The couple also share 20-year-old daughter Ella, while their son Jett died at age 16 in 2009.
Ella -- who is following in her parents' footsteps into acting -- recently praised her father as "the most incredible man I have ever known."
"Happy Birthday to the most incredible man I have ever known. You are not only the best Dad ever, but you are also my best friend," she wrote on Instagram last month. "Thank you for raising us, helping us and loving us and thank you for all of the good you do every day."
She concluded by writing that "the world is so lucky to have you and so are we. I love you Daddy. I had the best time celebrating your birthday with you yesterday. ❤️❤️❤️."