The Super Mario Galaxy movie confirms that Peach and Rosalina are sisters.

Peach and Rosalina from the Super Mario Galaxy Movie side by side.

Almost 20 years after Rosalina was first introduced in Super Mario Galaxy, the Super Mario Galaxy movie finally confirmed what her relationship with Peach was.

Considering that most Mario games have stories as simple as rescuing Princess Peach or whoever was kidnapped by Bowser that week, there really isn't much to theorize and wonder about. The only major exception to this rule is the identity of Rosalina, who was introduced in Super Mario Galaxy as one of the few characters in the franchise to have an actual backstory.

Rosalina's status as a princess and her similar appearance to Peach have led fans to speculate that the two are related for nearly two decades, with theories ranging from the two being sisters to theories that Rosalina is Mario and Peach's time-traveling daughter. These theories can finally be put to rest as The Super Mario Galaxy Movie fully confirms the relationship between the two.

Spoilers for the Super Mario Galaxy movie follow if you're into that sort of thing.

Peach and Rosalina's relationship is finally revealed

And yes, it's exactly what you think

Peach looks shocked by the Super Mario Galaxy movie.

In the first Mario movie, we were given a surprising amount of hints about Peach's background. Peach revealed to Mario that she was sent to the Mushroom Kingdom as a child (complete with an interesting star-studded costume), a nod to the Galaxy that had everyone speculating that Rosalina was somehow involved.

This tease continues from the beginning of The Super Mario Galaxy Movie, confirming once and for all that Peach and Rosalina are sisters living together in space. At the start of the film, the two are attacked and Rosalina (actually Peach's older sister) sends Peach to the Mushroom Kingdom to keep her safe.

That's a pretty big change considering how long Nintendo has gone without making Rosalina and Peach's relationship official, despite fans having held on to that theory since 2007. It will be interesting to see whether this family connection will be acknowledged in the game, or if it's something Nintendo continues to ignore outside of the movies.