Online movie-ticket seller Fandango has acquired movie rating websites Rotten Tomatoes and Flixster for an undisclosed amount.

The websites were bought from Warner Bros. Entertainment of Burbank, which will take an equity stake in Fandango. West L.A.’s Fandango will continue to operate as a unit of NBCUniversal.

Fandango purchased Rotten Tomatoes and Flixster for potential cross-promotional opportunities, Fandango President Paul Yanover said in a statement.

“Flixster and Rotten Tomatoes are invaluable resources for movie fans, and we look forward to growing these successful properties, driving more theatrical ticketing and super-serving consumers with all their movie needs,” he said.

The acquisition of Flixster and Rotten Tomatoes, which together reach 20 million unique visitors a month, will boost Fandango’s audience to more than 63 million unique visitors a month. Fandango’s U.S. ticket sales grew 81 percent last year.

Fandango has been on an acquisition spree in the past three months, buying up Brazilian online-ticket seller Ingresso.com for $71 million in November and movie-streaming platform M-Go of Culver City for an undisclosed amount last month.

Technology reporter Garrett Reim can be reached at greim@labusinessjournal.com. Follow him on Twitter @garrettreim for the latest in L.A. tech news.