The Just Married star was at GQ magazine's The Gentleman's Ball in New York City to present Yehuda Berg with an agent of change award for bettering society.

Kutcher told the crowd, "My best friend? Yehuda Berg. To me, he's not a rabbi. He's my friend.

"If you truly want to change the world, you have to start by changing yourself. (Berg) taught me that and it's been the most important lesson of my life."

Berg, who also advises Madonna and Gwyneth Paltrow, later spoke about the philosophy he has taught the star and his wife Demi Moore, explaining: "We used to think, 'Change the world, and eventually, my life will be better.' The truth is, if we change ourselves, the world will be better."

And he had a few words of praise for Kutcher and Moore, adding: "They're very special people. And she's a great mom. An amazing, amazing mom."