Jones and Smith return as Agents K and J in director Barry Sonnenfeld's latest Men in Black sequel, which also stars Josh Brolin as a younger version of K.
In an interview with The AP, Jones revealed that Smith has become one of his closest friends.
"Will is more generous than anyone, and he spreads joy," Jones said. "He walks into a studio, walks onto a set, and... he makes certain that everybody's happy. He can't help himself."
Jones also suggested that Men in Black films have been successful because he has a natural on-screen chemistry with Smith.
"Partnerships are good engines for narrative. If you think of Don Quixote and Sancho Panza, the Cisco Kid and Pancho, the Lone Ranger and Tonto. On and on," he explained.
Smith recently revealed that his young son Jaden Smith asked US President Barack Obama about the possible existence of aliens.
Men in Black 3 is now playing in cinemas worldwide.
Watch a Men in Black 3 trailer below: