The 'Not Big" hitmaker revealed on the social networking site Twitter.com that she had hidden two sets of seats for her sold-out performance at the House of Blues in San Diego, California.
"I'm gonna hide two sets of tickets, near the venue of the show. Await instructions," the Daily Express quoted her as stating on her blog. Allen later told fans to go to the venue's attic, and exchange some footwear for the pair of tickets, to which a fan obliged. "Ok, so the shoes have been handed in and traded for tickets, next clue coming up," Allen replied.
Allen later told fans to find fellow Twitter user rocio@thewyndham at the venue, who would hand over the final pair once serenaded with a song.