Adele's '25' Arrives: What to Expect in Terms of Sales

— -- The most-anticipated album of the year, Adele's "25," arrives today.

It goes without saying that the album -- which features songwriting contributions from Bruno Mars, Max Martin and OneRepublic's Ryan Tedder, will be super-successful. But just how big will it be? It's on track to shatter two records that have been held for more than a decade.

The first record that industry insiders predict Adele almost certainly will break is the one that Britney Spears currently holds: most albums sold by a female artist in a debut week. Spears' album "Oops!...I Did It Again" sold 1.32 million copies in a week back in 2000. The big one, though, is the all-time record for most albums sold in a week, which is currently held by 'N SYNC. In 2000, the boy band sold a whopping 2.4 million copies of their album "No Strings Attached" in a week. Some forecasters say 2.5 million is within Adele's reach.

"As we’ve seen with how 'Hello' has been tracking -- number one on the Billboard Hot 100 for the past three weeks -- that is a great indication of how people are reacting to Adele and her music," Billboard charts co-director Keith Caulfield told ABC News. "And of course, we can’t forget that her last album has done more than 10 million copies in the U.S."

He added with a laugh, "So, you figure at least some percentage of those people might wanna buy the new album when it comes out on Friday!"

"25," like Adele's previous album "21," will continue to sell and sell long after the holiday shopping period ends. It could stay on the charts for months to come, Caulfield predicted, citing Adele's universal appeal as a reason it'll fly off shelves.

"She reaches folks from 8 to 80. She’s able to reach people on an emotional level with catchy songs and emotions and words that really affect people," he said. "I think people feel like they’re hearing a good friend talk to them, like someone that they’d wanna spend time with. They not only love her voice and love what she’s saying, but they also really just like her. And you take that whole package together and I think that’s a really compelling artist."