Feb. 22 (UPI) -- Paris Jackson celebrated her younger brother's 15th birthday Tuesday.
The 18-year-old aspiring actress and only daughter of late singer Michael Jackson marked the occasion by dedicating a throwback post to Blanket, born Prince Michael Jackson II, on Instagram.
"ughhhhhh my little man is 15 today. slow the [expletive] down, i want you to stay a baby forever," Paris captioned an old photo of herself and Blanket making faces for the camera.
"this lil dude right here is one of the most strong, intelligent, and determined people i know. watching you grow up and slowly becoming a man is like super terrifying but i honestly can't tell you how proud i am. i love you so much B," she added.
Michael, who died at age 50 in 2009, was also dad to Prince, born Michael Joseph Jackson, Jr., now 20. People reported in June that Blanket, who was just 7 at the time of his dad's death, attends an elite private school in Los Angeles and enjoys martial arts.
"The siblings all remain close," a source told the magazine.
Paris, meanwhile, was recently spotted modeling at a photo shoot in Paris, and will make her acting debut on the Fox series Star. Prince praised Paris on Instagram this month after she wore a dress she co-designed to the Grammy Awards.
"So proud of my sister, not only did she address a crowd that big, but she designed a tasteful dress that expresses her individuality and uniqueness and she ROCKED it. Proud of you @parisjackson," he wrote.