Kanye West delivered the proposal of a lifetime to Kim Kardashian, complete with an orchestra playing 'Young and Beautiful' by Lana Del Rey, one of K.K.'s favorite songs. But when Del Rey was asked to perform the track, she denied him very flatly ... or did she?

The 'Born to Die' crooner is denying her denial. What happened?

TMZ cameras caught up with Del Rey as she was signing autographs for fans with boyfriend Barrie-James O'Neill. "I would never deny his request," Del Rey smiled. "That's not true."

The paps kept prying, asking her if she'd perform at West and Kardashian's wedding or who requested that she perform. Del Rey deftly dodged the queries by continuing to interact wth her fans instead of the instigating, nosy snappers. From the sounds of it? Purely speculation, but it sounds as if someone other than West -- we're thinking Kris Jenner of 'Keeping Up With the Kardashians' producers -- made the performance request, and that's why she turned it down. This gal doesn't need the cheap PR!