Tristan Thompson Attended Daughter True's 4th Birthday Party, He Is 'Very Involved': Source

A source tells PEOPLE that Khloé Kardashian and ex Tristan Thompson want their daughter True to "have the happiest childhood possible"

Photo: Khloe Kardashian/Instagram; George Pimentel/Getty

Tristan Thompson was by his daughter's side for her birthday festivities over the weekend.

A source tells PEOPLE that the NBA player, 31, attended the birthday party on Sunday that Khloé Kardashian threw for their daughter True, who turns 4 on Tuesday.

"Tristan shows up for every birthday and important event for True," the insider says. "He is a great dad. He is very involved."

The source adds that Kardashian and Thompson have been amicably co-parenting their little girl despite drama surrounding their personal relationship.

"Khloé gets along with him. The focus is on True and they have the same goals for her," says the source. "They want her to have the happiest childhood possible."

A rep for Thompson did not immediately respond to PEOPLE's request for comment.

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L: Caption . PHOTO: Khloe Kardashian/Instagram

C: Caption . PHOTO: Khloe Kardashian/Instagram

R: Caption . PHOTO: Khloe Kardashian/Instagram

Kardashian documented True's fun-filled day on her Instagram Story, showing off the pink and purple balloons, flowers and three-tiered birthday cake she got for her little girl.

For the adorable cat-themed party, True was all smiles as she rocked a pink feather-lined Dior dress and matching pink braids in her hair.

The festivities included a trampoline, bounce house and slide, ball pit, face painter and a pool. There was even an appearance from a performer dressed as a Squishmallow cat as well as Squishmallow party favors that said, "True, we hope you have the purrr-fect birthday!"

Kardashian also filmed True playing in the pool and admiring the custom M&Ms printed with her name and face on them — gifted to her by Rob Kardashian. The toddler even got to play with real kittens before posing next to a "Meow" yard sign.

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Prior to True's party, another source told PEOPLE that Thompson and Kardashian have "very little contact" with each other while co-parenting.

The Good American co-founder has been posting a lot on Instagram as she spends quality time with her daughter.

Last month, she took True out to a trampoline park and filmed their fun experience on her Instagram Stories. She recorded her little girl while chasing her around the room, pairing the clip to Bruno Mars' "Runaway Baby."

The Keeping Up with the Kardashians alum also shared clips of True bouncing on the trampolines, saying "Oh no!" as she lost balance and fell. In another clip, the toddler held her nose as she jumped into a foam pit.

Back in February, Thompson documented a night out at a restaurant with True. In a video on his Instagram Story, he smiled as he filmed True sitting next to him eating dinner. Thompson gave her a kiss on the cheek as she giggled.

"My favorite type of date nights ❤️🤞🏾," he wrote alongside the clip at the time.