A British woman who's become a celebrity in the U.K. because she was born with two fully formed vaginas may finally be able to cash in on her crotch ... TMZ has learned she's just been offered $1 MILLION to bone on camera.

Her name is Hazel Jones -- and the 27-year-old beauty has been making the media rounds across the pond to discuss "uterus didelphys" ... a condition which caused her to develop 2 sets of female reproductive organs. In other words, two vaginal canals with two openings.

Hazel recently told British tabloid The Sun that she's not shy about her condition -- insisting she and her husband have shown it off at sex clubs around the U.K.

Enter Vivid Entertainment honcho Steve Hirsch ... who heard Hazel's story ... and immediately reached out to the woman with a MASSIVE offer to film her double hoo-ha in action.

In the letter, Hirsch writes, "You are obviously an extraordinary woman and I would like to make you an offer to star in an upcoming Vivid production. We would pay you up to $1 million for your services."

For the mathematically challenged, that's $500k per vagina.

To sweeten the deal, Hirsch says Jones can pick any XXX partner she wants in her movie -- adding, "We would fly you out to L.A. as soon as you are available and provide you with first class accommodations."