"#ThrowbackThursday @nicolerichie and I being oh so cool at 13 years old," Kardashian captioned the pic, where both girls are giving their thumbs up to the camera as they smile in white shirts.
Richie, 32, who is wearing braces in the photo, retweeted the image with a fun spin.
"Brace Yourselves!" the mom of daughter Harlow, 5, and son Sparrow, 4, joked on Twitter.
Celebrity Couples of 2014 [PHOTOS]