How do you make mega star Pharrell Williams cry 'happy' tears? It's a simple three-step system perfectly executed by the queen of interviews, Oprah.

First, you ask him about how his song Happy went global.

Second, you show a video of people all around the whole wide world dancing and miming to his song.

Third, you pull out the grandma card.

Williams said of the video Oprah showed him, ‘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.’

We’re not saying Oprah knew that she would make Pharrell cry, but then she did pull out a handy pack of tissues…

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ELLE wears Pharrell's hat...