The Aussie actor, who plays Detective Steve McGarrett, says fans of the 70s cop show will get to hear him say the infamous catchphrase in the first episode of the remake.
"I've already said it, I've done it, it's in the can!" the actor revealed at the US premiere of his new movie The Back-Up Plan, which co-stars Jennifer Lopez.
"We're keeping the theme tune and I'm going to grow the quiff out and keep it sitting there like a banana," Alex laughed.
US TV bosses are currently deciding if they'll commission a full season of the show.
"It's been delivered, I don't know what's happening with it but I think it's going to be good," Alex said. "Scott Caan and I play McGarrett and Danno, they've put a lot of time and money into it."
The former Moonlight star joked he'd have to sharpen up his surfing skills should the show get commissioned.
"I'm a terrible surfer but I will learn to surf when we get over there," he said.