UFC legend Francis Ngannou revealed Monday that his 15-month-old son, Kobe, died on Saturday.

"I was my best self next to him, and now I have no clue of who I am," he wrote. "Life is so unfair to hit us where it hurts the most."

Francis Ngannou @francis_ngannou

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He also posted another message on social media Monday, while Conor McGregor was among those who reached out and expressed their sympathies:

Conor McGregor @TheNotoriousMMA

I am so sorry to hear of your loss Francis, my prayers are with you and your family at this time ❤️🙏

Ngannou's coach, Eric Nicksick, responded by asking fans to "please keep Francis and his family in your heart, and may this be a reminder of the fragility of life. Say 'I love you' more often, tomorrow isn't guaranteed."

The details of Kobe's death were not publicly made available.

Ngannou became a household name as a heavyweight champion in the UFC but recently switched to boxing. He lost his debut fight against Tyson Fury in a matchup that was closer than expected and then lost to Anthony Joshua in his second professional boxing match on March 8.