The 41-year-old singer cried out of happiness after Oprah, 60, showed him a montage of fan videos to his hit track 'Happy', reported Contactmusic.
"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," he said on the show.
Pharrell was particularly delighted by the song's success as it had struggled to get any radio play before its release.
'Happy' has topped musical charts almost all over the world.