Rocket League is being updated today to support cross-play between Xbox One and PC, developer Psyonix announced this morning. This is notable ("a historic moment in multiplayer gaming," the developer says) because Rocket League becomes the first Xbox One game to allow cross-play with PC.

Lionhead's Fable Legends was also going to offer cross-play between Xbox One and PC, but that game was canceled. The PlayStation 4 version of Rocket League already supports cross-play with PC.

Psyonix also announced today that almost 2 million people have now played Rocket League on Xbox One since its launch in February. That doesn't necessarily mean the game has sold that many copies on Microsoft's console, however. Whatever the case, cross-play with PC will undoubtedly increase the pool of available players.

When cross-play goes live at 3 PM PST / 6 PM EST today, Xbox One players can choose to include--or prohibit--PC players from their matches by checking a box in the Options menu.

"We're really excited to bring Xbox One and PC players closer together," Psyonix VP Jeremy Dunham said in a statement. "Cross-network play has been something that Xbox One gamers have been asking us for since the day we launched, and thanks to Microsoft's new cross-network policies, w''re proud to give it to them."

In March, Microsoft made a big announcement when it said it would natively support cross-platform play between Xbox One, Windows 10, and other "online multiplayer networks." The move effectively opens the Xbox Live platform so that it can accommodate players on Sony's PlayStation Network, among others.

There have been no Xbox One/PS4 cross-play games yet, but Rocket League could be the first, if it's ever allowed. Psyonix said it's not a technical matter holding it back, but rather it's an issue of politics.

"The only thing we have to do now is sort of find out where we stand politically with everyone, and then it's full steam ahead to finish the solution that we've already started," Dunham said in March.