The creators of "Shrek Forever After" have plenty of reasons to celebrate as the film beat two comedies and took the top spot at the Northern American box office for the third week in a row, according to studio estimates released on Sunday.

The animated film's strong staying power and estimated earnings of $25.3 million during the weekend send positive vibes for DreamWorks Animation SKG Inc, which saw its share price decline when the movie received a lower-than-expected opening.

"Families seem to be the ones really driving the box office and 'Shrek' being a great movie for everyone to see together, that seems to be working very well for 'Shrek,'" said Anne Globe, head of worldwide marketing at DreamWorks.

Producer Judd Apatow's sexy comedy "Get Him to the Greek" was at the No. 2 spot, earning $17.4 million in ticket sales in the U.S. and Canada.

"It's very interesting that Judd Apatow makes very responsibly budgeted films so it bodes well for the overall success in theaters and beyond," said Nikki Rocco, president of domestic distribution for Universal Pictures, the General Electric Co-owned studio that released the film.

"Get Him to the Greek" stars British actor Rusell Brand who is a brash rock star in the movie, along with Jonah Hill who plays a record label intern who needs to get him from London to Los Angeles for a concert date.

At No. 3 is the romantic comedy "Killers" starring Ashton Kutcher as a man with a secret job as a killer, and Katherine Heigl as his unknowing wife. It earned $16.1 million in both the U.S. and Canada.