In the hours after basketball legend Kobe Bryant was killed in a helicopter crash along with eight other people, thousands of fans began sharing their goodbyes on social media.

LeBron James added his own powerful, heartfelt message to those tributes on Monday.

The Los Angeles Lakers superstar -- whom Bryant often referred to as his "brother" -- shared a handful of pictures of the two on Instagram, saying, "I'm not ready but here I go."

"Man (I'm) sitting here trying to write something for this post but every time I try I begin crying again just thinking about you, niece Gigi and the friendship/bond/brotherhood we had," James wrote on Instagram.

Bryant and his 13-year-old daughter, Gianna, were killed on their way to a basketball game in Thousand Oaks, California, where Gianna was scheduled to play. With them was a community college baseball coach and his wife and daughter, an assistant girls basketball coach from Corona del Mal and a mother with her daughter, all on their way to the same game. The helicopter's pilot also died in the crash.

James said in his post he was "devastated and heartbroken."

"I promise you I'll continue your legacy man," he wrote. "Please give me the strength from the heavens above and watch over me! I got US here! There's so much more I want to say but just can't right now because I can't get through it! Until we meet again my brother!!"

The two had a special relationship.

Bryant's last tweet was a congratulatory message to James for passing him on the NBA all-time scorers list to claim the third spot. James has scored 33,655 points throughout his career. Bryant scored 33,643.

"Continuing to move the game forward @KingJames," Bryant tweeted on the night before the accident. "Much respect my brother."