Jenna Dewan took a family trip to Jurassic Park this Halloween.

On Thursday, October 31, the 43-year-old actress shared a series of photos on Instagram from his family of five as they posed as characters from Jurassic Park. The mother-of-three dressed as Alan Grant in khaki pants, a blue shirt, a red tie and a safari hat, while her fiancé Steve Kazee played Ian Malcolm, sporting a stylish all-black look with a leather jacket and small glasses.

Dewan’s oldest daughter, Everly “Evy,” 11, perfected the Elie Sattler look, wearing khaki shorts, a blue tank top and a red shirt tied around her midriff. Her son Callum, 4, smiled big and spread his wings in an orange pterodactyl costume. baby Rhiannon4 months old, stole the show, as the most adorable T-rex.

Never miss a story: subscribe to PEOPLE’s free daily newsletter to stay up to date with the best of what PEOPLE has to offer, from celebrity news to compelling human interest stories.

“Welcome to Jurassic Park ,” she captioned the carousel.

In one photo, the family poses in front of a green screen showing Jurassic worldand in another, everyone except Callum is hanging out atop a Jeep Wrangler. When a fan asked Dewan where her son was, she replied, “Pterodactyl wouldn’t stand still for photos…it was a brief sighting.”

The proud mom then shared more photos from their family photoshoot, this time focusing on the “Jurassic girls,” as Dewan captioned it. the position.

The mum-of-three can be seen posing with T-rex Rhiannon in one snap and leaning on Evy, who is on top of the jeep, in a second photo. Eventually, the three girls sit in the front of the Jeep and pretend to look for dinosaurs.

The PEOPLE Puzzler crosswords are here! How quickly can you solve it? Play now!

While chatting with PEOPLE at the InStyle Imagemaker Awards on Oct. 24, Dewan shared that she Evy and Callum are the best older siblings to Rhiannon.

“They’re great to her,” Dewan told PEOPLE at the event in Los Angeles. “They love him. They love him a lot, they love him a lot.”

“Callum in particular is really affectionate” and “Evy is obsessed with her and wants to hold her all the time and rock her and everything,” she added.