"PHARRELL WILLIAMS, the 'Happy' singer was joined onstage by Snoop Dogg, Nelly, P Diddy, Gwen Stefani and Busta Rhymes, Tyler, The Creator and Diplo at the 2014 Coachella Valley Music and Arts Festival on Saturday, The NERD man was joined by Nelly for 'Hot In Herre', Busta Rhymes and P Diddy for 'Pass The Courvoisier Pt. II', Snoop Dogg for 'Drop It Like It's Hot' and Gwen Stefani for 'Hollaback Girl'. He also played his own guest spots on Daft Punk's 'Get Lucky' and Robin…