Pharrell Williams Cries 'Happy' Tears During Oprah Chat

Well, he did write the song that makes the whole world sing.

Pharrell Williams, 41, couldn't help but get overcome with emotion as Oprah Winfrey, 60, played a clip of fans around the world, doing the "Happy dance" during a one-hour interview Sunday night.

"I don't know why I'm crying!" he laughed, as he wiped away tears, referring to the positive message of the video.

"It makes me cry, too!" Winfrey agreed.

Wearing his now-signature Vivienne Westwood hat, Williams also opened up about his astronomical past two years, from winning four Grammys and being nominated for an Oscar for "Happy," to his wedding to longtime girlfriend Helen Lasichanh, who is also the mother of his 4-year-old son, Rocket.

In fact, Oprah wanted to know why the couple chose the name Rocket.

"In the same way the Indians named their children after a force or animal or element, we named him after a man-made machine that was meant to go up, meant to ascend," Williams explained, noting he hopes he's destined for greatness.

He also talked about how he's adjusted to being the guy in the spotlight, after so many years working behind the scenes as a much sought-after writer and producer who has worked with Jay Z and Gwen Stefani. "I was happy being the guy standing next to the guy," he said.

Over the weekend, Williams made his Coachella debut, where he was joined onstage throughout his set by friends and past collaborators like Snoop Dogg, Nelly, P Diddy, Tyler the Creator, Busta Rhymes, Diplo and Stefani.