The beginning of the end arrives this weekend for worldwide fans of Warner Bros.’ “Harry Potter” franchise.

As the biz’s most successful series ever with $5.5 billion worldwide, Warner’s expansive global rollout for its second-to-last Potter pic, “Harry Potter and the Deathly Hallows: Part 1,” includes 4,125 U.S. locations, including a record-setting 356 Imax runs worldwide. “Hallows” also launches in 91 international territories.

Warners expected to attract plenty of eager Potter fans to the domestic B.O.’s 3,700 midnight runs Thursday. Last year, “Harry Potter and the Half-Blood Prince” set a late-night record with $22 million when it unspooled at 3,003 midnight engagements.

Playing second fiddle to the weekend’s Potter-mania, Lionsgate launches Russell Crowe starrer “The Next Three Days” at 2,564 locations.

Expect “Hallows” to play like a four-quadrant pic, attracting both young auds and adults who have grown up with the franchise. The film’s broad appeal may impact the specialty market,

though Fox Searchlight expands “127 Hours” to 108 locations, up from 22 last weekend.

The Danny Boyle helmed “127 Hours,” along with “Fair Game,” from Summit, have helped prop the specialty biz of late, turning in impressive per-screen averages, even with increased screen counts. “127 Hours” has cumed $944,052 so far, while domestic totals for “Fair Game” stand at $2.2 million.

While most B.O. observers predict “Hallows” will overshadow the series’ previous best “Harry Potter” opener “Goblet of Fire,” with $102.7 million in 2005, “Hallows” could have earned even more had Warner gone forward with its 3D treatment.

Last month, the studio pleased Potter fans and industryites when it announced it would forego the pic’s 3D conversion, citing the lack of time to finish the product.

“This (franchise) is the Holy Grail at Warner Bros.,” said Warner distribution exec Dan Fellman. “And there was no way we were going to go out with something that wasn’t up to the quality of the franchise.”

The “Harry Potter” franchise has been a massive cash cow for Warner, not only with box office grosses, but also ancillary and merchandising profits. “Hallows” splits J.K. Rowling’s final installment in two, a decision made to boost profits and to include more material from the 700-plus page tome.

Still, some detractors have described “Part 1” as the slower of the two versions, with most of the action happening in the adaptation’s second half. Warner will release “Part 2” in 3D on July 15. Director David Yates returns for both “Hallows” pics, after directing the two previous Potter pics. Other series mainstays include scripter Steve Kloves and producer David Heyman, who have collaborated on all eight films.

“Hallows” has been building steam with fans for weeks leading up to its release.

Pic stands as the fourth-highest advanced ticket seller ever for MovieTickets.com, accounting for 96% of ducats sold Thursday, and the third for Fandango.

Lionsgate reps described the weekend as an opportunity to establish “Next Three Days” with adult auds. But with “Hallows” also appealing to moviegoers over 25, that may be a tough sell for Lionsgate. The distrib said it expects the pic to range between $7 million-$10 million for the weekend.

Based on a French-language film, “Next Three Days” tell the story of married couple, played by Crowe and Elizabeth Banks, whose lives are upended when the wife is arrested for murder. Director Paul Haggis also wrote the film, based on a script by the original French scribes Fred Cavaye and Guillaume Lemans.

Among the frame’s holdovers, 20th Century Fox’s “Unstoppable” enters its second frame after posting $22.7 million. Paramount-DreamWorks Animations’ 3D toon “Megamind” topped last weekend, with $29.1 million. “Unstoppable” has cumed $27.5 million through Wednesday, while totals for “Megamind” reached an impressive $92.3 million.

Universal’s low-budget sci-fi pic “Skyline” debuted in fourth place last weekend and has grossed $13.7 million; Par’s “Morning Glory,” another soph-sesh title, has totaled $14 million so far.

Elsewhere on the specialty front, Sony Classics launches a limited release for Brit comedy “Made in Dagenham” at three locations in New York and Los Angeles. IFC’s French-lingo pic “White Material” also goes out at three, while the distrib’s “Heartless,” with Jim Sturgess and Eddie Marsan, launches this weekend in New York.