Beyonce and Jay-Z doing an On The Run summer tour, eh? July 4th weekend in Philly just got a lot more intense

[youtube http://www.youtube.com/watch?v=sybScJtgwbc&w=620&h=315]

Go to about 2:30 on the above video, if you wish. Beyonce is doing "Upgrade U" live in Los Angeles, wearing a flowery yellow dress, and suddenly, Jay-Z -- who is a part of that song if you were to purchase it on iTunes -- emerges from beneath the stage to do his part, sending the crowd into…