IT didn’t take long for Thailand college students to realise that the female teacher on the front of their brand new maths textbooks was a porn star.

They had seen her somewhere else apparently.

The pretty woman, posing with glasses and a folder, is actually Japanese X-rated actress Mana Aoki.

Publisher MuangThaiBook has confessed to using a screengrab from her steamy movie, Costume Play Working Girl, for the front page of its Basic Mathematics textbook.

About 3000 copies were sent out to 10 universities before the mistake was noticed.

The textbooks are now all being recalled and will be reissued with a different cover, according to RocketNews24.