While he's given many great performances, Josh Brolin's turn as a young Agent K in Men In Black 3 might be his most unsung. The first Men In Black movie was based - very loosely - on a comic series of the same name. Actors like Clint Eastwood and Chris O'Donnell were considered for the roles of MIB veteran K and rookie J, but Tommy Lee Jones and Will Smith eventually took the parts. The movie was a robust mix of comedy and blockbuster action, with the chemistry between the two leads making it work.
Men In Black was a huge blockbuster but it took a few years for the sequel to come together. While Men In Black II was another success, it grossed less than the original and received much colder reviews. It would take another decade for Smith and Jones to suit up again for Men In Black 3 - which was also Smith's first film after a four-year hiatus. It proved to be the highest-grossing of the series to date, but after a crossover between the franchise and 21 Jump Street called MIB 23 was mooted and rejected, the next instalment was Men In Black: International. Despite reteaming Chris Hemsworth and Tessa Thompson from Thor: Ragnarok, this entry was a critical and commercial dud, meaning it could be sometime before the series returns.
While Men In Black 3 isn't a classic, it's easily the best of the sequels. The story sees Smith's J travel back in time to 1969 to save a young K from being killed by a vengeful alien fugitive called Boris the Animal (Jemaine Clement). Since most of the story takes place in 1969, this naturally means Tommy Lee Jones' take on K is absent from most of the plot, with Josh Brolin taking over as his younger counterpart. Brolin had worked with Jones on other films and director Barry Sonnenfeld was so convinced he was perfect for the role that he rejected the notion of Mark Wahlberg for the movie.
While a modern-day blockbuster might have had Tommy Lee Jones play the role himself and de-aged him - to questionable effect - Men In Black 3 wisely opted for an actor who was able to capture his essence. While Brolin bears a slight resemblance to a younger Jones, everything from his body language to his mimicry of the older performer's voice is spot-on in the movie. It really feels like watching Tommy Lee Jones, but the performance goes beyond mere impersonation.
Josh Brolin's K in Men In Black 3 is a little looser than his older counterpart and he brings depth to the character. The ending reveals that J's father was a Colonel who was killed by Boris after saving K's life and that K has been secretly watching over J his whole life. Brolin is particularly affecting when comforting the young J, which leads to a touching final scene between older K and J in the movie's final scene. So not only did Josh Brolin's K get to play comedy and drama in Men In Black 3, the actor also gave the world's best Tommy Lee Jones impression for good measure.