Who plays in the music video you write sins not tragedies by Panic at the Disco?

In the music video for "I Write Sins Not Tragedies" by Panic! At The Disco, the lead vocalist Brendon Urie plays the main character who witnesses a wedding. The video features a storyline that revolves around themes of infidelity and the chaos of the wedding event. Other characters include the bride and groom, along with various guests who contribute to the dramatic narrative.