If you're an international musical superstar about to announce the follow-up to your biggest-selling album ever, why be coy about it?  Katy Perry hired a gold-plated semi-truck to break the news for her.

Katy tweeted Monday, "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."  It didn't take fans any time at all to figure out that pretty big clue or to spot the hard-to-miss rolling billboard and begin posting photos of the semi as it drove around Los Angeles, with the words "KATY PERRY -- PRISM -- 10-22-13" emblazoned on the trailer in six-foot-tall letters.

Even Adam Lambert spotted the semi and posted a photo of it to his Twitter, writing, "Yes @katyperry this is crazy!! Love it!"

Prism will be the follow-up to Katy's multi-platinum international smash album Teenage Dream, released three years ago next month.