LBJ sat down for an interview with ESPN's Michael Wilbon ... and when the topic of Kyrie came up, it wasn't hard to see the King was heartbroken the Lakers got beat out by the Mavericks in a swap for the Nets superstar.

"Definitely disappointed," James said. "I can't sit here and say I'm not disappointed."

James called Irving someone he knows he has great chemistry with -- and someone who "can help you win championships."

The 38-year-old, though, said he's already getting over it ... telling Wilbon, "My focus has shifted back to where it should be, and that's this club now and what we have in the locker room."

As we previously reported, Irving was sent to Dallas on Sunday after he requested a trade last week. As part of the swap, Dallas sent over Spencer Dinwiddie, Dorian Finney-Smith, a first-round pick and a handful of second-rounders.

L.A. reportedly tried hard to get into the mix for Irving -- as did the Heat, Suns and Clippers.

James and Irving previously had success in Cleveland, when they went to four consecutive NBA Finals. They won a title in 2016 after overcoming a 3-1 deficit against the Warriors.

After news broke that Irving was on the move from Brooklyn to Dallas, James sent out an eyebrow-raising tweet that said, "Maybe it's me."

It's unclear who or what James was referring to, though the timing was interesting. But, either way, the four-time time NBA champion says he's moving past the disappointment of it all.