'Fifty Shades of Grey' will have the best President's Day Weekend ever at the box office

Analysts grossly underestimated the allure of "Fifty Shades of Grey" at the box office.

The adaptation of E.L. James' BDSM novel about a naive virgin and a billionaire playboy took in $81.7 million opening weekend.

Analysts expected the movie to open north of $60 million. The movie cost an estimated $40 million to make.

That's the second-largest opening weekend ever in February.

The only movie that made more was 2004's "Passion of the Christ," which debuted to $83.8 million.

That number also makes "Fifty Shades" the fifth-largest opening weekend for an R-rated movie behind "The Matrix Reloaded," "American Sniper," "The Hangover Part II," and "Passion."

By the end of the four-day weekend, "Fifty Shades" is predicted to make at least $90 million, which would easily give it the largest President's Day weekend at the box office. Currently, 2010's "Valentine's Day" holds that record with $63.1 million.

We wouldn't be surprised to see a final higher number for "Fifty Shades" over the four-day weekend.

Not only was the film one of Fandango's top advance ticket sellers of all time, but it was also the ticket service's top February pre-seller and the biggest R-rated ticket-seller for the company.

Overall, the movie has made $239.7 million worldwide so far.

And it wasn't just "Fifty Shades" that had a good weekend.

The other big release this weekend, "Kingsman: The Secret Service" brought in $35 million. Analysts expected the movie to make a smaller haul in the lower $20 millions.

The Fox film starring Colin Firth and Samuel L. Jackson cost $81 million to produce.

Last weekend's SpongeBob Squarepants movie, "The SpongeBob Movie: Sponge out of Water," had a strong second week with another $35.6 million. That movie also beat analyst expectations when it opened to $55 million.