The “Stranger Things” actress went totally under the sea, with a themed look and cake for the milestone event.

The Goddess of Pop, 78, looked glamorous as usual ... simple jewelry and a platinum blonde updo.

She accessorized with crystallized open-toe heels and diamond earrings, wearing her dark tresses in a tousled updo. Jenner’s makeup included rosy blush, taupe eyeshadow and a matte terracotta lip.

Also in the line-up is a girl wearing a traffic cone on her head; a sliver-haired female in marching band regalia, armed with a pair of swords; and a girl with pink braids and a pilot hat who could ...