The Essex-born contestant shared two images of himself completely nude behind the scenes at Cosmopolitan - one taken from the front with only his hands covering his modesty, and one from the back.
He also told his 495,000 fans that he was "having a great old time" posing as the magazine's naked centrefold.
Clark recently expressed hope that The X Factor will mark "the start of the rest of [his] life".
"It's changed my life. Hopefully, it will open doors for me," he said.
"I've always wanted something like this, but wanting it and actually having it happen are two different things."
It has also been revealed that Clark was one of 2012's top Facebook trends, beaten only by the London 2012 Olympics and erotic novel 50 Shades of Grey.
Watch Rylan's interview with Digital Spy below: