The 'Fallout' franchise recently hit almost five million players in a single day.
Fallout has hit some impressive milestones
Developer Bethesda has hyped the amazing milestone across all 'Fallout' games, which follows the debut of the hit Amazon Prime Video TV adaptation earlier this month.
Taking to X (formerly Twitter), the team said: 'Thank you to the over one million of you who adventured with us in #Fallout76 in a single day... and almost five million across all Fallout games in a single day!"
They added: "Holy Moly!"
The studio didn't specify which day the milestone occurred.
However, the game's player numbers have been rising since the series launched on Prime on April 10.
'Fallout 76' creative director Jonathan Rush teased more "exciting moments" to come.
He tweeted: "It’s amazing to see the large influx of new Appalachian Adventurers, and how our awesome community has welcomed them!
"A very exciting moment with many (many) more to come! #Fallout #Fallout76 #Xbox"
Currently, both 'Fallout 76' and 'Fallout 4' are in the top 10 best selling games on Steam, as well as being in the platform's top 50 most played games.
Meanwhile, the current generation free update for 'Fallout 4' will arrive on April 25, giving players the option to choose between Performance and Quality modes, while offering up to 60fps support and "increased resolutions" on the most powerful systems.