In pop-culture terms, it has been forever since the Men in Black franchise's last installment.

And now, 10 years after the sequel and 15 after the original film, agents J (Will Smith) and K (Tommy Lee Jones) are back in black and ready to save the Earth, again.

To say that no one was clamoring for a Men in Black 3 (MIB 3) would be an understatement. The announcement of the franchise's third installment came with a sense of impending flop.

"With something like Men in Black, a sequel is actually more difficult than the original," Walter Parkes, who has produced all three of the films, told the Los Angeles Times.，

"The challenge is to be fresh and original but also deliver on the core values of the franchise."

Then, what's the magic of this franchise that makes Sony Pictures more than willing to approve a budget of millions even after a decade?

Star power

"Before Smith starred the 1997 original film, he was this rapper-turned actor who impressed the audience with Independence Day. Everyone was wondering whether he was a one-hit wonder," The New York Times movie critic A.O. Scott wrote.

Things are different now. The first Men in Black has achieved so much success that it made Smith an A-list star. And look at him now–a box-office guarantee.

Innocent and wacky

Having achieved the hybrid creation of cutting-edge yet nostalgic aliens, the franchise succeeds in maintaining the innocent and wacky take on old Hollywood creatures.

"Films about aliens usually end up being dark, violent and scary, but the Men in Black series goes a different way–light-hearted, comedic, and even a little bit cynical," Ben Fritz wrote in his review for the Los Angeles Times.

"Like Steven Spielberg's E.T., a warm, touching story about an alien."

Buddy movie

At the core of Men in Black is the relationship between agents K and J. Somewhere between the aliens and space travel there's a story about two partners–a futuristic take on those timeless themes of friendship, loyalty and extraterrestrials.

Funny and intelligent

And to judge by what's on screen, the filmmakers not only managed to overcome their strife, they have created one of the satisfying summer popcorn movies.

It's a funny, intelligent film shot through with strong performances by Smith and Josh Brolin (who plays a younger version of agent K), and an emotional finale.

"Yeah, there were some issues. And you've seen some media reports about overages and runaway production and no script. That was all true," Barry Sonnenfeld, director of all three of the Men in Black films, told AP.

"Ultimately, the movie delivers. And the audience isn't going to care."