Nathaniel Marshall -- Former 'American Idol' Contestant Now Doing Gay Porn

Nathaniel Marshall -- who made the top 36 on season 8 of "American Idol" in 2009 -- is now trying his hand (and a few other appendages) at a new career ... gay porn.

Marshall, now using the porn name Jadyn Daniels, is appearing in a film called "Men Caught on Video 2" which became available just yesterday. The movie does not appear to have much of a plot, so if you like your porn with a gripping story ... this is not the one for you.

Marshall/Daniels isn't the first reality star to transition into gay porn -- Steven Daigle, who appeared in "Big Brother 10," moved into the gay XXX biz 18 months after he left the show.