Gwyneth Paltrow is having a hard time accepting that her youngest child is turning 15.
Taking to Instagram on Thursday, the Oscar winner celebrated her son's birthday with a sentimental message.
MORE: Anna Faris and Gwyneth Paltrow reflect on the lessons divorce taught them"Holy Moses I can’t believe you are 15 today," Paltrow gushed, while sharing two photos of her son. "You are the dreamiest, sweetest, most brilliant guy ever. I love you so much, you can’t fathom it."
The first photo is a closeup of Moses' face, while the second shows the teen doing a kickflip on a skateboard. "Happy birthday you little shredder," the proud mom concluded.
Several of Paltrow's famous friends flooded Moses with birthday wishes of their own, such as Reese Witherspoon sweetly remarking, "Happy 15th Moses!"
MORE: Gwyneth Paltrow reveals what triggered her partial retirement from actingPaltrow shares Moses and daughter, Apple -- who turns 17 in May -- with ex-husband Chris Martin. Paltrow also recently shared a snap with Apple, describing her daughter as "one of the absolute loves of my life."
The "Iron Man" star has since remarried television director Brad Falchuk.