James Harden knows Russell Westbrook well. 

The two were not only teammates for three years in Oklahoma City, but have been friends since the age of 10, Harden explains in a recent interview with GQ.

But Harden also knows there will be growing pains when the two play together again.

In one of many shocking NBA offseason moves, the Thunder and Rockets completed a trade sending Chris Paul to Oklahoma City and Westbrook to Houston for a reunion with Harden.

“It’s like, yo, we’ll figure it out,” Harden said. “Everything isn’t necessarily going to be smooth at first, there are going to be ups and downs, and that’s part of an 82-game season. Hopefully, by the end of the season, we’ve caught a rhythm and everybody is on the same page going into the playoffs. That’s all you can ask for.

He added: “There’s a different kind of relationship and communication that we have, a different type of excitement that we have for each other. We don’t really care or pay attention to what other people say or think.”

Harden was complementary of his once-again teammate and former NBA MVP.

"He’s a great dude. A lot of people don’t know him off the court, because they don’t have an opportunity to get that personal with him. Everyone sees this guy on the court who’s so “crazy” or “passionate” or “wild” or whatever," he said. "Yeah, his on-the-court game is his on-the-court game. But off the court, he’s genuine, one of the most loving dudes that you will ever be around."

The Rockets decided to trade away Paul, whose relationship with Harden reportedly soured last season, for two protected first-round draft selections and two pick swaps to secure Westbrook.

Houston fell to the Warriors in six games in the Western Conference semifinals last season after going 53-29 to claim the fourth seed.

Now, Harden and Westbrook will pair up on a similar team to what the Rockets had last year.

"We’ve formed into the players that we want to be, in terms of superstar status," Harden said. "We had opportunities to be at the top, at the peak; he won an MVP and I won an MVP. And there were conversations before when me and Chris [Paul] joined the same team about whether it was going to work. We ended up with the best record in the NBA and were a game away from the Finals."