Zynga's latest game "CityVille" has overtaken its other game "FarmVille" to become the most popular app on social networking site, Facebook.

CityVille now has 16.8 million daily active users against FarmVille's 16.4 million, according to AppData. As for active monthly users, CityVille is ahead with 61.7 million users, while FarmVille had 56.8 million users.

Two other games from the developer, "FrontierVille" and "Texas HoldEm Poker" were also in the top five. The other game in the top five is "Phrases," which is behind both "CityVille" and "FarmVille."

CityVille had a very good start at the beginning of December and has attracted millions of users.