During an episode of "Oprah Prime" with Oprah Winfrey, "Happy" singer Pharrell Williams became so overcome with emotion that he actually burst into tears.

The tears were inspired by the success of his hit song and its impact on listeners that he couldn't even begin to imagine when he wrote it.

"It's overwhelming because it's like I love what I do," said Williams, "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 the video and make sure you've got a box of tissues handy!