The fourth and final film in the "Twilight" teen vampire series is in the works, TheWrap has learned.

With the sequel to the blockbuster hit "New Moon" now filming in Vancouver and its sequel, "Eclipse," already deep in the planning stages, an individual close to the production has told TheWrap that work on the fourth and final in the series, "Breaking Dawn," will start in late spring 2010.

Summit Entertainment spokesman Paul Pflug declined to confirm or deny the report, saying only, "Summit has no comment on that rumor at this time."

The planning for "Twilight" IV means that the blockbuster series based on Stephenie Meyer's popular vampire drama has come to dominate the production schedule of Summit Entertainment.

It also means that the obsessive fan base of the movies can expect to revel in no fewer than three full-length "Twilight Saga" films -- going from November of this year through the end of 2010.

But a Summit executive who declined to be identified said that there was no production schedule for "Breaking Dawn," and no current plans to shoot in Vancouver. 

"New Moon" is scheduled for release on Nov. 20, while "Eclipse" has a tentative release date of June 2010. A fourth in the series would logically be scheduled for release before the end of next year.

That means even more pressure on a full-throttle production schedule past the end of this year. Fans of the book will remember that the action through the novels takes place in a relatively short period of time, unlike, say, "Harry Potter."

"New Moon," directed by Chris Weitz and with a reported $50 million budget, is slated to wrap in late May and go into an accelerated post-production for that late fall 2009 release date. Stars Robert Pattinson and Kristen Stewart and the other leads will get a couple of months off, then return to Vancouver in late summer 2009 to begin work on "Eclipse," whose director has not yet been chosen. Summit has denied reports in the blogosphere that Juan Antonio Bayona, who helmed 2007's "The Orphanage," had won that gig.

Shooting on "Eclipse" will come to an end just as Pattinson and Stewart get ready to hit the promotion circuit for "New Moon." Once their duties around the world on the red carpet for the first sequel are complete, they will have only Christmas holidays and a few months off before heading back to Vancouver for "Breaking Dawn."

By then Vancouver, visited recently by TheWrap, will have become accustomed to the fervor surrounding the "Saga."

Even though Summit only sent out a statement on April 15 that principal photography had started on "New Moon," production actually began in March, setting Vancouver abuzz for weeks, with fans following the production around from location to location, often alerting each other via Twitter.

In mid-March, the cast and crew were spotted by locals filming under the title "Unnamed Sports Movie," at Tofino, the surfing hot spot at the far northern tip of nearby Vancouver Island. Then, early in April, locals spotted the books' author, Stephanie Meyer, on set at David Thompson Secondary School, and new cast member Taylor Lautner was among the cast and crew at the westside Ridge Theater art house.

The set is enforcing a cone of vampiric silence, with extremely tight security, with even extras required to sign waivers and nondisclosure agreements. But there's a lot of speculation among the locals and the news media following the production around.

With Meyer visiting on-set, rumors abound that the author is finessing the script -- written by Melissa Rosenberg, who also did the first "Twilight" movie -- to include more of heartthrob Pattinson's character, Edward Cullen, who is absent for significant portions of the actual "New Moon" novel.

The addition on March 30 of British actor Jamie Campbell-Bower ("Sweeney Todd") and, two weeks later, "Frost/Nixon's" Michael Sheen, has led to rumors that other big changes are coming to the adaptation. Pattinson has also suggested in recent comments that fans will be surprised when they see the film.

Most days, the production has had two units shooting. This past week, work began in the suburb of Coquitlam during the day and in the forests bordering the hilly neighborhood of West Vancouver at night.

Visiting the set has been impossible for locals, fans and the media, both local and international. "Last week the production tried to keep me back by claiming that they owned Burnaby Park while shooting there," said Rik Fedyck, one of Vancouver's most successful paparazzi. "They said their permit gave them the whole park," he laughs, "I checked their permit with City Hall and it was only for the parking lot in the public park."

One notable exception is Entertainment Tonight, which has an upcoming exclusive from the set. Correspondent Thea Andrews was in Vancouver earlier this month filming an on-set visit that is set to air on April 23, the first day of Nielsen's spring sweeps. (Check out Andrews' "New Moon" Twitter feed. [1])

Released on Nov. 21, 2008, the first "Twilight" film, directed by Catherine Hardwicke, brought in $380 million in worldwide box office, with a production budget of just $37 million. That may end up being merely a deposit on the profits that the entire "Twilight Saga" will bring in over the next couple of years.

And that will certainly get Hollywood's blood pumping.