How do i change the aspect ratio from 4:3 to 16:9 on little big planet gameplay for ps3?

i just got the game little big planet for my ps3 and when i started the game on my hdtv it was displayed on a 4:3 aspect ratio but i have my display setting set to HDMI with a 16:9 aspect ratio or widescreen. want to know how to change the gameplay to an HD display. no guesses please.How do i change the aspect ratio from 4:3 to 16:9 on little big planet gameplay for ps3?its in the little big planet settings menu. its a slider that you move left or right that makes the display bigger or smaller. hope that helps