The countdown is on for 'Transformers: Revenge of the Fallen,' in theaters and IMAX June 24, and only ET has the exclusive details on Shia LaBeouf's hand injury, kissing Megan Fox -- and the largest explosion in film history -- from Shia and Megan themselves!

"It's the best action film you'll see this summer; it has the biggest explosions of any action film," Shia tells our own Mark Steines of the fireball that made the Guinness Book of World Records. "They told me about ten minutes before we did it. I'm looking at these canisters, just all this gas … and I see about 40 of our special effects team way off to the side -- I mean way off."

As for that headline-grabbing injury last year when Shia injured his hand in a car wreck, Shia says there was no choice but to write the injury into the movie's plot: "Yeah, I think it had to be, no other way to make [the] movie," he says, adding, "I just had another surgery about 10-11 days ago on it. Prognosis is solid, my doctor's really happy. I'm in good shape. This is the best it's been in a long time, so I feel good, things are really good."

Of course, Shia and Megan find time to pucker up in the middle of the movie's action and mayhem, and while Shia remembers doing only "something like five takes," Megan recalls, "We shot that scene all day. Clearly he enjoyed it!"

So, is Megan a good kisser? "Yeah, absolutely," Shia says. "I think she'd say I'm pretty good too." Megan responds, "I've said it before, he's a really good kisser. It's always awkward, you're on set with a bunch of grown men, sweaty, sitting outside, carrying camera equipment and wanting to take their break, and you're having to kiss. But luckily we didn't have any real intimate scenes -- it's a pretty innocent kiss on the street!"

Megan also says she's comfortable with her sex symbol status, saying, "I think it's wonderful. I didn't decide I'm gonna be an actress because I want to be respected for how I play chess. Part of Hollywood is being perceived as attractive."

For more movie news and exclusives, head over to ETonline's Summer Movie Guide!