Posted by babu 4:09pm GMT
Katy Perry's key to instant cool? Her "Frank 2" Super shades.
Here, the singer is shown rocking the two-toned, retro glasses all over Los Angeles and New York.
Photos: Splash News
!["How I Met Your Mother"](http://mylt.ltcdn.com/d6/sites/mylifetime.com/files/images/imagecache/carousel_159x119/2011/01/12/HIMYM-159x119.jpg ""How I Met Your Mother"")
