His music might be happy but Pharrell Williams couldn't help but cry on Oprah.
The American singer-songwriter appeared on Oprah's show, Oprah Prime, and broke down in tears of happiness when watching a compilation of fan-made videos for his song Happy.
"Why am I crying on Oprah?," he asked rhetorically.
The reason was the song had brought happiness to people around the world.
The fans' videos showed people from Malawi to Taiwan happily dancing and enjoying the song.
They were part of a viral explosion of fan-made videos since a revolutionary 24-hour music video of Happy was released last November.
It consisted of the four-minute song repeated over a continuous 24-hour period, with various people - including celebrities such as Jamie Foxx and Steve Carell - dancing and miming the lyrics in Los Angeles.
Pharrell told Oprah the response had been bigger than he could have imagined.
"Zero air play, nothing," he said.
"And next thing you know we put the video on November 21st - all of a sudden, boom.
"It's overwhelming, because it's like I love what I do, and I just appreciate the fact that people have believed in me for so long that I could make it to this point to feel that."
Watch more of the interview here:
And get a full dose of life-affirming happiness with Pharrell's original video here: