updated 04/14/2014 AT 1:00 PM ET
•originally published 04/14/2014 AT 2:00 PM ET
Well, he did write the song that makes the whole world sing.
“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.