Get ready to be swamped by Snow White

Julia Roberts in Mirror, Mirror. Photo / supplied

Hollywood's Snow White rivalry is heating up.

Movie studio Relativity Media on Thursday pushed back the US release of its light-hearted fairytale starring Julia Roberts, Mirror Mirror, by two weeks to March 30.

That cuts the time between it and Universal Picture's pulsating action movie, Snow White and the Huntsman, to nine weeks instead of 11.

Relativity insists its PG-rated version of the Brothers Grimm story is a family comedy while Comcast Corp's Universal is marketing Huntsman as a gritty medieval thriller featuring a plate-armour-wearing Kristen Stewart and axe-wielding Australian actor Chris Hemsworth.

Both studios are betting that the audiences won't overlap. After Relativity cut the gap, Universal did not immediately change its planned June 1 release in the US.

Most movies make the majority of their ticket sales in the first few weeks after they debut. Still, Hollywood is betting the quick turnaround won't turn off people who might want to see both movies.

Relativity said the date change puts Mirror Mirror within a week of the potentially lucrative Easter weekend. The studio also said the change made sense given a recent reshuffling of other movies, such as The Raven, which will now come out on April 27 instead of March 9 in the US.

Another theory is that Relativity is jumping out of the way of 21 Jump Street, a comedy starring Jonah Hill and Channing Tatum. That movie comes out on the same weekend Mirror Mirror had planned on.

Early positive reaction from bloggers and journalists has encouraged Sony Corp's Columbia Pictures to market 21 aggressively, and Relativity might not have wanted to risk coming second at the box office that weekend.

In the past, back-to-back releases of similarly themed movies haven't harmed their appeal.

In the most recent example, Deep Impact and Armageddon each sold well more than $US300 million in box office tickets worldwide despite coming out less than two months apart in 1998. Both movies featured space objects that threatened to destroy Earth.

Snow White and the Huntsman, starring Aussie Hemsworth, releases in Australia on June 21

21 Jump Street releases in Australia on March 15.