The Keeping Up With The Kardashians star was seen spending the day with Bieber at the Cove Resort at Atlantis in the Bahamas back in June.
Writing on her official website, she said: "Remember those paparazzi pics of me and Justin Bieber in the Bahamas!? Well, I can now reveal that we were shooting for Elle magazine! (sic).
"I just received the pics from the shoot and I absolutely LOVE how they turned out! The theme of the shoot was The Graduate for obvious reasons, LOL."
She added: "Justin and I had such a fun time together at the shoot. "
Kardashian and Bieber were later seen catching up over frozen yoghurt in Los Angeles last month.