According to police, the woman was stabbed on southbound C train near Chambers Street just after 8 a.m.
They say there was a verbal dispute between the victim and a male suspect, but it appears they did not know each other.
The victim was taken to Bellevue hospital in stable condition.
Officials say the suspect fled the scene.
They describe him as approximately 50 years old and wearing a black jacket and blue jeans.
No arrests have been made.
Ex-Brit turned Manhattan resident since 2008.