Howard is directing the racing movie, which focuses on the rivalry between James Hunt (Chris Hemsworth) and Niki Lauda (Daniel Brühl) during the 1976 world championship season where Hunt won the title and Lauda staged a remarkable comeback weeks after a near-fatal accident.
Speaking to BBC F1's Eddie Jordan at the Monaco Grand Prix, Howard explained: "The characters offer so many surprises. It's a great screenplay, when I read it I didn't know very much about Formula 1 or these guys, and I was just knocked out by the script by Peter Morgan. He's great. We did Frost/Nixon together. He also did The Queen. He's a great writer.
"With those kind of characters, you get drama, you get surprises and then, of course, there's this unbelievably cinematic possibility, which is capturing your world, capturing Formula 1 - particularly in the '70s, which was a pretty reckless, sexy time."
Howard also reiterated his desire to show Formula 1 fans that he has "respected" the sport's heritage with the movie, and explained that he hopes newcomers will be drawn to the sport as a result of Rush.
"I also want people who don't know much about Formula 1 to really appreciate these characters, look at the sport and think, 'Man, I've been missing something', and if I can accomplish those two things then I think I've done my job," he added.
Howard also confirmed that principal photography on Rush is now complete and he hopes that the movie will be out in spring 2013.
Photo gallery - Chris Hemsworth and Olivia Wilde film 'Rush' wedding scenes: