Mahiki is William and Kate's favorite nightclub, where they flirted over cocktails and went wild after their famous split in 2007.
"At the end of the night, oh my God...It should come with a warning," a Mahiki patron told McInerney.
McInerney also ordered a cocktail that literally explodes on the bar!
Her next stop was Piccadilly Circus, London's party central. The streets were packed with people and buzzing with excitement about the upcoming nuptials.
Another favorite London hotspot is the Wyld Bar at the W Hotel, a tequila bar where the bartender was happy to give lessons in shaking cocktails.
It's an inside look at the scene where Will and Kate went from wild 20-somethings to bride and groom.