ET sat down with the 39-year-old athlete on Tuesday to talk about his new "Do Nothing" campaign for UGG -- a five-part digital series also featuring actor Jeff Bridges and New England Patriots wide receiver Julian Edelman -- which celebrates the "art of doing nothing." Not surprisingly, on his own time off from football, Brady's life revolves around his wife, supermodel Gisele Bundchen, and raising their two children -- 6-year-old Benjamin and 3-year-old Vivian -- as well as 9-year-old John, whose mother is actress Bridget Moynahan.
"Well, [off time] is usually focused around the kids, you know, you spend so much time with them and trying to be a parent -- which is such an important part of our lives -- so, whatever they're into, that's kind of what you do," Brady exclusively told ET's Jennifer Peros. "You try to support them and the things that they're doing, and encourage them in different ways."
Brady is definitely letting his children find their own interests in life and not pushing them to follow in their famous parents' footsteps. In fact, Brady says he's careful about introducing football to his sons.
"We've had a lot of soccer games and baseball games -- we haven't had too much football -- we're trying to incorporate that slowly, or at least I am, especially for the boys," Brady admits. "But they're into soccer and baseball, so it's fun to see ... to play with them keeps me in good shape."
"The interests they'll find ... those will be for them to kind of sort out over the years," he continues. "They're all so young at this point. It's fun to see their personalities grow and develop, to see them work hard at things and see them improve."
Brady reveals that both John and Benjamin have an idea that their parents are famous, although Vivian is oblivious given her young age. The elite athlete admits that when it comes to his little girl, she definitely has him wrapped around her little finger.
"It's the worst -- well, it's not the worst for me, I think it's the worst for my wife who's trying to instill some discipline in her and I just give her whatever she wants," he jokes. "But isn't that what men are supposed to do for daughters?"
"Yeah, there's princesses, and My Little Pony dolls, and it's just the cutest thing ever," he adds.
But Brady's definitely the disciplinarian between him and Bundchen when it comes to their children.
"I'm the final 'no,'" he shares. "And once they hear dad say 'No,' they know it's a permanent no."
As for his new haircut, Brady laughs off all the attention and jokes concerning his new 'do, which some have compared to heartthrobs in 90's TV shows like Saved by the Bell and Boy Meets World.
"I think there's a lot of things at this point that are ridiculous that are covered, but that's just the way it is," Brady says.
But he has the last laugh, seeing as his supermodel wife has no complaints.
"She usually likes whatever I do," he says about his style. "She always kind of likes it."
"She's my best friend," Brady gushed. "We spend as much time as we can together, and you know, it's a busy life we have and we have three kids."