Mules by Blue by Betsey Johnson, Embellished bow, Slip-on style, Pointed toe, Open back, Flat sole, Get low, get low. Blue by Betsey Johnson is the iconic designer's bridal footwear edit, combining fashion-forward thinking with her classic whimsical vision. The result is a collection of embellished mules and heeled sandals to take you from ceremony to dancefloor, with each pair finished with a signature blue sole.