Jon Gosselin's ex-girlfriend Hailey Glassman will be starring in a horror flick with famed porn star Sasha Grey.

And -- don't get insecure Jon -- but there's a possible lesbian scene in the works too!

"Hailey was approached to read for a small role in the movie and did so well that they called her back for a larger role," a source close to casting told RadarOnline.com exclusively.

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