f(x)' Sulli tread the line between innocent girl and sexy woman for the April issue of 'InStyle'.

She left her cute image behind for the photo shoot with Canadian shoe and accessories brand ALDO, going for a more mature look instead. The idol star definitely looks more grown up wearing dramatic red lipstick and feminine, formfitting outfits, but she still managed to hold onto her girlish appeal.

Check out a preview of her photo shoot from next month's 'InStyle' below, and let us know what you think of Sulli's looks!