The McCarthy women are celebrities now, but back in the day, they were just kids posing for a family photo.
“102 degrees at the zoo, not happy campers,” Jenny, 24, captioned the retro picture of the outing.
Melissa, 44, is an incredibly successful TV and movie star today – her next project is the all-female Ghostbusters reboot – and Jenny helped her get her start in Hollywood.
“When she was starting out, I was fortunate enough to be in a position to get her a job on a show I was doing, to learn the ropes and get some experience on a TV set in front of the camera and behind the scenes,” Jenny told PEOPLE last year.
“She has accomplished everything she has accomplished through hard work and her extraordinary talent,” she added, “and I’ve only ever encouraged and supported and wished her the very best.”