On May 7, 2014, Cher confirmed a collaboration with American hip hop group Wu-Tang Clan on their album "Once Upon a Time in Shaolin". Credited as Bonnie Jo Mason, she uses an alias of hers originated in 1964. Only one copy of the album has been produced, and it was sold by online auction in November 2015. It is the most expensive single album ever sold. After appearing as Marc Jacobs' guest at the 2015 Met Gala, Cher posed for his brand's fall/winter advertising campaign. The fashion designer stated, "This has been a dream of mine for a very, very long time."