Tristan Thompson Says He Will 'Always Protect' Daughter True in Sweet Birthday Tribute: 'My Baby'

Tristan Thompson/Instagram

Tristan Thompson shared a sweet message to his daughter True in honor of her 4th birthday.

On Tuesday, the NBA player, 31, shared a series of cute photos and videos of the daddy-daughter pair on his Instagram Stories to celebrate True's special day.

Thompson, who shares True with ex Khloé Kardashian, first posted a clip of the two snuggling before the athlete gives True a kiss on the cheek.

"Happy birthday momma I love you soo Princess ❤️," he wrote. On the following slide, Thompson posted a selfie of the pair in which his face is covered with stickers. "Can't believe my baby is 4 🤦🏽‍♂️," he added.

The Chicago Bulls player also included a photo of him posing with True and his son Prince, 5, whom he shares with Jordan Craig, writing, "Prince and Daddy love you soo much Tutu ❤️ We will always protect you🙏🏽"

Never miss a story — sign up for PEOPLE's free daily newsletter to stay up-to-date on the best of what PEOPLE has to offer, from juicy celebrity news to compelling human interest stories.

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

The last photo featured little True in her pajamas smiling while wearing a gaming headset. Thompson teased in the caption, "You will always be my number 1 pick in Fortnite duos momma ❤️"

Earlier this week, a source told PEOPLE that Thompson attended the birthday party that Kardashian threw for their daughter True.

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

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

Khloe Kardashian/Instagram; George Pimentel/Getty

"Khloé gets along with him. The focus is on True and they have the same goals for her," said 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.

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

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!"