In a surprise move, Warner Bros. has moved the release date of “Harry Potter and the Half-Blood Prince” from Nov. 21 to July 17. Warners president Alan Horn blamed last winter’s 100-day WGA strike in large part for the shift, suggesting all the major studios have been hurt in the development of new tentpole films for next summer.

“We are still feeling the repercussions of the writers strike, which impacted the readiness of scripts for other films — changing the competitive landscape for 2009 and offering new windows of opportunity that we wanted to take advantage of,” Horn said. “We agreed the best strategy was to move ‘Half-Blood Prince’ to July, where it perfectly fills the gap for a major tentpole release for midsummer.”

The move also reflects execs’ belief that the “summer season is an ideal window for a family tentpole release,” he said.

Warners had hoped to have a franchise-launching movie based on the “Justice League of America” comic book ready for next summer, but the project was shelved indefinitely during the WGA strike.

Warners opened the previous Potter movie, “Harry Potter and the Order of the Phoenix,” to $77.1 million in July 2007 en route to $292 million domestically. It represented the second-biggest grosser in the franchise’s history after the 2001 original.

The studio said it will release a two-movie adaptation of the final book, “Harry Potter and the Deathly Hallows,” as planned. “Deathly Hallows: Part I” is set to unspool Nov. 19, 2010.

Read the rest at The Hollywood ReporterSOURCE: THR