Facebook game The Sims Social has debuted with with 4,859,046 million monthly active users after leaving public beta.
842,032 new users have started playing the title today, with 3,665,510 joining in the last week.
The game is published by EA and developed by PlayFish, the social gaming developer acquired by EA in 2009.
"When we created The Sims Social, it was important for us to incorporate the deep gameplay nuances The Sims Studio has perfected and leverage what Playfish does best- develop compelling, cutting-edge social-gaming experiences," said John Earner, GM of Playfish's London Studios.
"Our deep knowledge of the Facebook gaming platform enables us to continue to enable dynamic new features, quests and game updates on a regular basis so The Sims Social remains fresh and fun."
The game has been in development since October, a relatively long time for a Facebook title, and will offer items from advertising partners, such Dunkin' Donuts, in game.
"The Sims Social brings the authentic life-simulation game design that only The Sims can deliver, and melds it with truly intuitive social-interactive features," added GM of EA Play Lucy Bradshaw.
"The Sims Social gives our fans tools to express their creativity, experience the unpredictability of Sims' personalities and live out their dreams, all while enabling them to connect, engage and play with their friends."
Currently Cityville is the most popular Facebook game, with nearly 76,000,000 MAU. At is peak it had over 100 million. CityVille managed 22 million MAU after 11 days live, and The Sims Social seems to be on track to challenge that figure.
The Sims is the best selling PC franchise in history, with over 100 million copies of Sims games sold and a dedicated online community.