LeBron James says his emotional reaction to the death of Gregg Popovich's wife came "straight from the heart" but clarified that he was not blindsided by the news on live television.

The San Antonio Spurs announced the passing of coach Popovich's wife Erin on Wednesday, leading to an outpouring of tributes around the NBA.

And Cleveland Cavaliers star James - with whom Popovich has long shared a mutual respect - was asked for his reaction following his team's 100-97 defeat of the Indiana Pacers.

Tearing up and appearing surprised as he took a moment to gather his thoughts, James told TNT: "Obviously, I'm a huge Pop fan. I love Pop. That's such a tragedy.

"My best wishes goes out to Pop and his family. That's devastating news. It's a lot. The NBA family, we all stick together. I know we compete every night, but when something like this happens it puts everything in perspective.

"I send my well wishes and my prayers up to the heavens above. I know the man above never makes a mistake even when you sometimes have to ask why.

"That's just terrible news. Best of luck to Pop, everybody in San Antonio, the whole Spurs family. That's all I can say."

But James later clarified that the question, from TNT's Allie LaForce, did not catch him off guard as had been suggested on social media, with the reporter warning him beforehand of the news that broke during the game.

"I'm not on social media right now, but I was made aware through some friends, through texts, that a question was asked to me post-game and a lot of people feel like I was blindsided," James said in a video posted on Uninterrupted's Twitter page.

"That is absolutely false. Allie LaForce told me that she was going to ask me the question and [asked] if it was okay.

"That was just my emotions coming straight from my heart about the late Erin Popovich. It's unfortunate, it's a tragic loss. My thoughts, my prayers once again go out to the Popovich family, to Gregg, to the Spurs family, to the whole Spurs fan base.

"Also, guys, please get off Allie LaForce's back, because she followed the proper protocol and she warned me. Get off her back, man. She's very professional and she does a great job at her work."