He said "I'll be back," and he wasn't lying: Arnold Schwarzenegger will return to the role that made him famous in the upcoming "Terminator: Genesis." But as MTV News found out when we sat down with the actor to discuss his upcoming movie "Sabotage," some things have changed.

"It will be challenging because it will be a new director, and it will be a really action packed movie," Schwarzengger said of the movie, which starts shooting in April. "And sometimes it does get more difficult when you're 66 years old and doing this kind of action, versus when you're in your 30s or in your 40s."

Which brings up an interesting question. "Terminator" introduced Schwarzenegger's time-traveling killer robot in 1984, when the actor was a mere 37 years old. He last played the T-800 model in the 2003 threequel "Terminator: Rise of the Machines," which was over a decade ago. And robots don't age -- right?

"The way that the character is written, it's a machine underneath," Schwarzenegger continued. "It's this metal skeleton. But above that is human flesh. And the Terminator's flesh ages, just like any other human being's flesh. Maybe not as fast. But it definitely ages."

As far as we know, this is a new wrinkle in the continuity of the "Terminator" franchise, and potentially one to accommodate the self-admittedly older Arnold. So we'll get to see an older robot, and not a younger one Ô right?

"Terminator deals a lot with time travel, so there will be a younger T-800," Schwarzenegger added, blowing our minds, "and then what that model does later on when it gets reprogrammed, and who gets ahold of him. So it will be all kinds of interesting twists in the movie, but I feel so good."

We're also feeling good about this, as the "Terminator" series has been far more concerned with robot-fueled action than the actual mechanics of time travel.

It's been a constant in the series through every iteration except for "Terminator Salvation;" which was also the one entry in the series that didn't feature Arnold (though his CGI head and body did show up at one point); but never the focus.

"I was upset that I couldn't be in the fourth Terminator, because I was Governor," Schwarzenegger remembered. "So they did the fourth one without me, it made me cry a little bit. But I did say, 'I'll be back,' so now I'm back again and it's going to be really terrific."

"Terminator: Genesis" will hit theaters on July 1, 2015. "Sabotage" is in theaters on March 28.