Warner Bros.' annnounced Tuesday that its upcoming fantasy epic “Clash of the Titans” will indeed be converted into 3D and its release date will be pushed back a week to April 2, setting off a wave of calendar rejiggering by rival studios.

With "Clash" moving from March 26, CBS Films announced Tuesday that its Jennifer Lopez romantic comedy “The Back-Up Plan" will move from April 16 to April 23. One rival-studio distribution official said that with "Clash" moving into early April, and other films likely to push their release dates back in its wake, April 16 had become too crowded for what will be CBS Films' second release.

MGM, meanwhile, pushed comedy “Hot Tub Time Machine” to March 26, and Fox moved back kids book adaptation “Diary of a Wimpy Kid” to March 19. More April juggling is expected.

Some of these moves aren't directly tied to the repositioning of "Clash," which, according to one rival-studio distribution executive, will likely carry a PG-13 rating.

However, another distribution executive said "Clash's" move was the catalyst for most of the April scheduling volatility.

“Everybody’s getting out of the way of the 800-pound gorilla,” he said.

In addition to "Clash," Warner also announced Tuesday that its upcoming seventh and eighth installments of "Harry Potter" will be converted to 3D. [1] "Cats and Dogs: The Revenge of Kitty Galore (set for release in July) and "Guardians of Ga' Hoole" will be converted to the funny-glasses format, as well.

Pushing the Legendary Pictures-produced "Clash" back a week will enable Warner to obtain enough 3D screens for its release in the format. The 3D exhibition realm will be tied up through March, with Disney's Tim Burton-directed "Alice in Wonderland" debuting March 5 in the format, and Paramount/DreamWorks 3D-animated "How to Train Your Dragon" set for March 26.