20 HUGE Hit Movies NOBODY Saw Coming

7. Mamma Mia!

Even with the global love for Abba and the huge success of the Mamma Mia! musical, there was no guarantee that the film adaptation would be a sizable hit, especially as it released within spitting distance of what would become 2008's highest-grossing film, The Dark Knight.

But this ultimately proved to be a masterful feat of counter-programming, as Mamma Mia! enjoyed strong holds for weeks, enough that it ended up topping out at $706.4 million worldwide on a $52 million budget.

With the riskiness of musical adaptations and the fact that large swaths of its cast weren't classically trained singers - looking at you, Pierce Brosnan - Mamma Mia! could've certainly been a modest performer at best.

But it was the feel-good hit of the summer that audiences needed in 2008, and though 2018's sequel Mamma Mia! Here We Go Again didn't hit the same high note, it still made off with a solid $402.3 million against its $75 million budget.