Now play CityVille on Google+

Zynga added its most popular title -- CityVille -- to games that can be played at the Google+ social network recently launched in a challenge to Facebook.

"It's no secret we're big fans of Google+ here at Zynga," the San Francisco-based startup said in a blog post.

"Last month we announced that we partnered with Google to bring Zynga Poker to Google+, and today we're excited to add CityVille+ to the new game platform," the message continued.

In August, Google+ opened a gaming zone at the fast-growing social network vying with Facebook to be the hub for people's online lives.

Along with global game sensation Angry Birds, the initial array of offerings available at Google+ included Bejeweled Blitz, Zynga Poker, and Dragon Age Legends.