Chris Pratt celebrated son Jack's milestone 13th birthday with a handful of sweet family photos. "I have a teenager???" Pratt, 46, wrote via his Instagram Story on Sunday, August 17, alongside his heartfelt tribute. "Jack, I can't believe you are 13 today. I've watched you grow into such an incredible young man, and am truly proud of the person you are becoming. I love you! Jesus is King! ." Among the pics included in Pratt's collage was a snap of himself and Jack wearing matching jerseys with their last name on the back.