Travolta, 68, shares Ben and daughter Ella Bleu, 22, with late wife Kelly Preston, who died at age 57 in July 2020 after being diagnosed with breast cancer. The couple also share son Jett, who died at age 16 in 2009.
Travolta adopted Peanut for his son after Jamie Lee Curtis brought the dog — formerly Mac N Cheese — on stage at the 94th Academy Awards as she honored Betty White and her dedication to animal welfare.
Ella also celebrated her little brother on social media by posting a sweet picture of Ben holding the adorable pup by his side.
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"Happy Birthday to the sweetest boy I know❤️🎉🐶 I love you!!!" she captioned the post.
In August, Travolta shared an impressive video on Instagram of Ben practicing his parkour skills at an indoor adventure gym, noting that his son recently achieved a new ranking in his training, becoming a "level 3 ninja."
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In the clip, Ben jumped between a series of objects by using monkey bars to swing across. He also moved a metal bar up and down a series of pegs using only his upper-body strength.
"I'm so proud," the actor said at the time. Ella also cheered on her brother in the comments section, adding, "🎉🎉👏."