The Toronto International Film Festival (TIFF) has decided that it’s time to force filmmakers and studios to make a choice: If you want a prime slot at our fest, stay away from Telluride.

After finding that its highest profile films were increasingly screening at the Telluride Film Festival a few days before coming to Toronto, TIFF organizers have told studios that its prestigious first-weekend bookings will this year be restricted to films making their world premieres or North American premieres.

TIFF Artistic Director Cameron Bailey told TheWrap on Tuesday that he “delivered the news to the film companies we work with” in a trip to Los Angeles this month. The move was first reported by Anne Thompson at Indiewire.

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Telluride takes place in the Colorado mountain town over Labor Day weekend, while Toronto begins the following Thursday. Although TIFF runs for 11 days, its prime films are typically scheduled for the first Friday, Saturday and Sunday, with many press and industry visitors leaving town after the weekend.

The Telluride-Toronto two-step has become popular in recent years, with Oscar winners “Argo,” “The King’s Speech” and “Slumdog Millionaire” all playing in the mountains before heading north.

In 2013, films that stopped in Telluride before going to Toronto included “Gravity,” “Blue Is the Warmest Color,” “The Invisible Woman,” “Labor Day,” “Prisoners” and “12 Years a Slave,” which screened as an unannounced surprise entry at Telluride.

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All played on the first weekend in Toronto, which also showcased the Telluride titles “Tim’s Vermeer,” “Gloria,” “The Lunchbox,” “Palo Alto,” “The Unknown Known” and “Gloria,” among others.

Because Telluride does not announce its lineup in advance and does not bill its offerings as premieres, films typically play there but are still presented as premieres at later festivals. But the large number of prime contenders screening in Telluride has clearly rankled Toronto organizers, who talked about getting tougher on double-dippers during the festival last year.

Coupled with the New York Film Festival’s demand that the key titles in its late-September fest be world premieres, the TIFF rule has the potential to hurt Telluride programming, if studios and filmmakers want the showcase provided by the far larger and more well-attended festival.

But if enough films choose to hang onto the more intimate and less overwhelming environment in Telluride, it could also turn the typically-frontloaded Toronto festival into an event where the key titles are unveiled over an entire week or 10 days rather than crammed into a frenetic opening weekend.

Bailey also said that the opening-night film at TIFF must be a world premiere, and the closing-night film a world or international premiere.