The proud mom, 31, took to Instagram on Saturday, March 30, and shared several photos and videos of preparations for the celebration.
Pictures show tents being set up in a backyard with the Jersey Shore members behind the scenes.
The duo seems to be on good terms. The television personality pans the camera over to Ronnie's brother at one point.
Brother James cracks a joke making Jen laugh. The actress then showed that his grandmom and "auntie" were there.
In a clip, Jen stands next to Ronnie, 33, and asks, "Why do you look so nervous?" before she cut out and showed footage of a "1" birthday balloon and their daughter riding in a pink toy car.
This is the second time the pair has been spotted together since their split. They attended a party in Texas with their daughter on Sunday, March 24.
Ronnie and Jen, who began dating in July 2017, welcomed Ariana in April 2018. Their on-off relationship included cheating allegations and the actress' arrest for domestic battery in June.
They had broken up earlier this year following a New Year’s Eve fight.
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