Rockstar Games' anticipated action shooter "Red Dead Redemption 2" will not be released until spring next year. However, the developers recently announced a mission in "Grand Theft Auto Online" ("GTA Online") that will unlock a weapon for the upcoming game.

The "secret" mission was first discovered by game file data miners The Guru Team. Rockstar Games officially announced the crossover not long after the discovery.

Upon looking at the game files for the latest "GTA Online" update "The Doomsday Heist," The Guru Team found references to "Red Dead Redemption 2."

They discovered that there were assets associated with "Red Dead Redemption 2." For instance, there was a chest and a note that reference "Boles Overland Stagecoach Company." This is a company name that was mentioned in the trailers for the upcoming game.

As confirmed by Rockstar Games, there is indeed a mission in "GTA Online" linked to "Red Dead Redemption 2." It is a scavenger-hunt type mission, which ultimately rewards the players by unlocking a double-action revolver for the upcoming game.

The mission kicks off when "GTA Online" players receive an in-game e-mail that speaks about "rumors of a lost relic from the frontier." The players will then be lead to explore San Andreas. They will be prompted to take photos of the various landmarks that they encounter.

After completing this mission, players will be rewarded with a new gun— a double-action revolver.

Once the players have the gun, they can participate in the "Headshot Challenge" in Freemode. When they complete the challenge, they will receive $250,000 in-game cash in "GTA Online." In addition, a similar double-action revolver will be unlocked for "Red Dead Redemption 2" when it comes out.

Whether the weapon will be available for single-player only, multiplayer, or both are not specified in the announcement.

"Red Dead Redemption 2" is currently under development by Rockstar Games. It is expected to be released sometime during Spring 2018.