Los Angeles, California - Tristan Thompson honored his "best friend" Khloé Kardashian on the reality star's 40th birthday.

The NBA star gave his ex, whom he shares two kids with, a sweet shoutout on social media Thursday.

"Happy birthday Khloé!" he wrote via his Instagram story. "You are the best mom. You are my best friend. And the most incredible human being I've ever met."

Khloé reposted one of Tristan's photos, which featured her alongside the 33-year-old athlete's brother, and added, "Thank you TT! I appreciate this!"

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The former flames have been amicably co-parenting their little ones, True and Tatum, since their last split in 2021. But as this season of The Kardashians has shown, Tristan hasn't given up hope that the two may eventually rekindle their romance.

Khloé, though, hasn't been interested in revisiting the relationship, which was infamously marred by repeated infidelity on Tristan's part, and she hasn't been seeking out new suitors either.

In a recent episode of the Hulu series, the Good American mogul admitted that she holds some fears about dating again, particularly worrying about how it might negatively affect her kids.

"So much has already transpired that could potentially f**k them up that I don't want to add to that by bringing somebody new to mix 'cause so far, people have been very disappointing," Khloé said.

Nevertheless, KoKo is confident she'll still find her "fairytale" ending and hopes to get married again one day.

Tristan's tribute wasn't the only surprising b-day message shared Thursday, as Khloé's older sister, Kim, also penned a heartfelt post honoring her despite the heated feud currently playing out between them on season 5 of The Kardashians.