Pharrell Williams has been reduced to tears when he appeared on Oprah Winfrey's talk show.
The chat show host surprised the Happy hitmaker with a montage of fan-created videos from around the world, inspired by his number one song, which made him cry on Oprah Prime.
"Why am I crying on Oprah?" laughed the seven-time Grammy winner.
"It's overwhelming because 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," he said through his tears.
Pharrell, who wore his signature Vivienne Westwood hat on the show, said the tune's success has been a huge surprise.
"(It had) zero airplay, nothing. And the next thing you know, we put out the video and all of a sudden, boom. We were like, what's happening? People are like putting up their own videos, it was like no longer my song," he told Oprah.
Oprah replied: "I get it. I really get it."
Written and produced by Pharrell, Happy - which featured on the Despicable Me 2 soundtrack and Pharrell's new album G I R L - topped the charts in 24 countries including the UK, US and Australia. It was nominated for an Oscar but lost to Let It Go from Frozen.