The actor took to the stage under the guise of a Comic-Con visitor dressed in a cheap Spider-Man Halloween costume before revealing himself to be Andrew Garfield, much to the delight of those in attendance.
Garfield then began an impassioned speech about his love for Spider-Man and how much it means for him to play Peter Parker in Marc Webb's upcoming reboot.
"Stan Lee says that the reason why Spidey is so popular is because all of us can relate to him, and I agree. I needed Spidey in my life when I was a kid and he gave me hope," Garfield began. "In every comic I read he was living out my and every skinny boy's fantasy of being stronger, of being free of the body I was born into, and that swinging sensation of flight.
"And upon receiving his power, unlike most who have become corrupted, he used it for good," Garfield continued. "And I think that we all wish we had the courage to stick up for ourselves more, to stick up for a loved one more, or even a stranger you see being mistreated, and Peter Parker has inspired me to feel stronger. He made me, Andrew, braver.
"I wouldn't be able to stand here in front of you guys right now without feeling that Spider-Man was here with me with his reassuring hand on my shoulder, making sure I don't fall over and concuss myself," the actor went on to explain. "I owe Webhead a lot and I owe Stan the Man a lot and I'm humbled to be here, like you do not know, to share the work that we've done with all of you.
"This is definitely the coolest moment of my life and thank you for being here to share it with me," Garfield added.
Watch Andrew Garfield's full speech at Comic-Con International below:
The film stars Garfield as a teenage Peter Parker opposite the likes of Emma Stone, Rhys Ifans, Martin Sheen, Sally Field and Irrfan Khan.
The Amazing Spider-Man will open in US and UK cinemas on July 3, 2012.
Digital Spy is bringing you exclusive videos, pictures and live panel blogs from Comic-Con all weekend - view our full coverage of the event here.
Watch the new trailer for The Amazing Spider-Man below: