The 27-year-old actor, who died in a freak accident when he was crushed by his Jeep at his home in Los Angeles in June 2016, is the subject of film "Love, Antosha", which is directed by Garret Price.
Pine introduced footage from the documentary at the Hollywood Forever Cemetery – where Yelchin is buried – ahead of a special screening of Star Trek commemorating the 10th anniversary of the sci-fi film's debut.
"Obviously we're here for Anton; he was one of my dear friends and I felt like I was only getting a chance to know him a better one when he passed," the 38-year-old told the audience.
"The film is incredible and I think it'll show you all different sides of the guy that I knew – this curious, fascinating, complex, strange little dude," he touchingly added of the actor who played Pavel Chekov in the rebooted "Star Trek" trilogy.
"We saw him grow up and continue to get stranger, more curious – (about) music and literature and photography. You'll see all that in here," Pine said of the documentary. "I think it's a great legacy for whom I had a tremendous amount of respect and for this courageous young man who just had zero fear and boundless, endless positivity and, an energy for life.
Pine later told Variety it was "really difficult" to sit down to talk about his late friend, because he'd never lost someone he was that close to.
"It was doubly difficult, but also joyous in the sense that I got to remember and talk about a guy that I really liked and was interested by, and every time I got a chance to hang out with him, always showed us a strange new side of himself that made us laugh," he candidly shared.