Tim McGraw is adding to his list of all-star projects with this weekend’s premiere of his latest film, Tomorrowland, a futuristic project with what cast members believe has a great deal of heart.

“You know art and what you do and … you know growing up around music, there’s got to be an honesty to it and there’s got to be a heart, and you have to lead with that,” McGraw tells CMT Hot 20 Countdown.

As for Tomorrowland, he adds, “It’s entertaining and has all the bells and whistles and all the cool stuff that’s going on, but at the end of the day, there’s a great heart to it. That’s what I liked as much as anything.”

The elements of hope and positivity were clearly present in the Tomorrowland script, a factor co-star George Clooney says was refreshing given many of today’s current news headlines.

“First, it’s the director … Brad Bird who’s done The Incredibles and Ratatouille and Iron Giant,” Clooney says. “He’s really talented. He hasn’t done a bad film. We’re friends, and we wanted to work together. And then they brought me this script, and the first thing that you look at when you read it is, you go, ‘Every time you turn on the television now, it’s really bad news right now.’

“It’s been a rough few years of really hard news -- hard on your soul -- and this was a movie that was optimistic. It wasn’t an apocalypse at the end like all the movies are now. It really was saying there’s a better world out there, and it’s within your grasp.”

The optimistic theme wasn’t the only reason McGraw and Clooney agreed to sign on for the project. Decisions were made easy with a roster of cast members including Britt Robertson and Raffey Cassidy.

“When you’ve been around as long as I have, doing so many different things, the best things that you want to do are work with people that you admire and people that you feel like you can get a lot out of,” McGraw says. “People that you feel like can make you better at what you do and you can learn something from. And Brad Bird, George, Britt and everybody involved with the project -- you know, a Disney project -- it’s pretty cool, so all the elements fell in place for me.”

Tomorrowland opens nationally Friday (May 22).

For more from the cast, watch the all-new episode of CMT Hot 20 Countdown this Saturday and Sunday (May 23-24) at 9 a.m. ET/PT.