Katy Perry has continued to tease her new album around California.
A huge gold truck emblazoned with the words "Katy Perry Prism", followed by the date "October 22, 2013" on its top, back and sides has been making its way around Los Angeles. It is rumoured to be the title and release date of the upcoming record, although neither Katy nor her record label have confirmed that the truck is related to the album.
The glitzy vehicle was previously spotted in Los Angeles, where singer Adam Lambert posted a photo, and Katy tweeted a picture of it driving across the Golden Gate Bridge in San Francisco.
"GOLDEN 2X," she wrote.
The Teenage Dream songstress previously tweeted to her 40 million followers: "Find the #PRISM semi, take a picture and I'll RT you. Don't worry, Los Angeles is just the first stop on the map."
Katy, who reprises her voice role as Smurfette in The Smurfs 2, has revealed that her fourth album, the "darker" follow-up to 2010's Teenage Dream, will be inspired by her personal life.
The 28-year-old, who has rekindled her romance with John Mayer, also said she has been influenced by Madonna.
"I think Madonna, especially in the beginning of her career when she was laying the foundation, was evolving every single time and giving a new visual and a new idea to the public... I just hope to be the same. I hope to continually make people interested and hopefully in 10 years look back and have written songs that have become timeless," she told L'Uomo Vogue in June.