Amitabh Bachchan
Taught Braille script in Black and English in Chupke Chupke
The Big B has been a part of this nobel profession quite a few times -- he played school principal in Mohabbatein and professor in Kasme Vaade -- but his most memorable role as teacher was when he taught Rani Mukerji (playing a deaf, mute and blind student) to make an identity for herself.
And of course, there was Chupke Chupke where he was forced into teaching Botany to his love (Jaya Bachchan).
Also read: What connects Taare Zameen Par, Tom Cruise