The royal sisters Elsa and Anna have pulled in an impressive $1.3 billion at the box office, and the hit movie is also extremely popular in the toy aisle this holiday season, bringing in almost the same amount in merchandise sales.

Disney’s Frozen is the animation studio’s largest hit since 1994’s “The Lion King,” and has established a property that ranks among the toy industry’s greatest holiday hits, joining a short list that includes Tickle Me Elmo, Furby and the Cabbage Patch Kids.

“It has been a great run and fun to watch,” said Laurie Schacht, president of toy and licensing publisher Adventure Publishing. “I think it has exceeded all expectations. The shelves are basically empty of Frozen products, but [retailers] have also been restocking.”

Sales of “Frozen” toys, games, shirts and more could hit $1 billion in the United States alone this year, giving Disney (DIS), as well as toy manufacturers Mattel (MAT) and Jakks Pacific (JAKK) a massive boost at a time when overall retail sales for the key holiday season appear choppy. For Mattel, “Frozen” has been a blessing as sales of the company’s iconic Barbie have been in steep decline. Jakks Pacific, which found itself mired in the red after some missteps on internally developed toy lines, is again profitable thanks to sales of Frozen-related gear.

Retailers have taken note. Wal-Mart (WMT) has more than 700 Frozen items, while Toys ‘R’ Us has more than 300, and eBay (EBAY) says there are over 40,000 listings for Frozen gear on its website. Although these retailers say they have bulked up on orders for Frozen gear, they may have underestimated just how popular this line would be. The popular Elsa Snow Glow doll, for example, is selling for as much as $60 on eBay (it retails for less than $30, but has often been out of stock both online and in retail stores this holiday season).

“Whenever we bring Elsa Snow Glow back online, she sells out quickly,” said Wal-Mart representative Jaeme Laczkowski.

Wal-Mart said Frozen has been the most highly searched entertainment property on its website since the film debuted in November 2013, so the property has been on its radar for a while. And the retailer plans to add additional Frozen gear to its shelves in the final days before Christmas.

“Stores have been limiting the Snow Glow sales to two per customer,” Schacht said.

Many toy fads eventually see their popularity dim, but Schacht sees a bright future for Frozen for the next few years, pointing out that an ice show based on the film is selling out and doing so well that dates are being added to the tour. There are also some rumors that a sequel could be in the works. That’s all good news for Hasbro (HAS), which gets to begin making dolls based on Disney’s princess and Frozen properties beginning in 2016.

So for those parents hoping to finally get “Let It Go” out of their heads, it appears this is the song that has no end.