All that we know is not completely true. There are many changed names in Bollywood and obviously we know only a few. Here is the list of Bollywood celebrities (both living and dead) whose names are different in reality and something else on screen. List is given in alphabetical order.
Aamir Khan - Aamir Hussain Khan
Ajay Devgan - Vishal Devgan
Ajit - Hamid Ali Khan
Akshay Kumar - Rajiv Bhatia
Amitabh Bachchan - Amit Srivastav
Ashok Kumar - Kumud Ganguly
AR Rehman- Dilip Kumar
Bobby Deol - Vijay Singh Deol
Dev Anand - Devdutt Pishorimal Anand
Dharmendra - Dharam Singh Deol
Dilip Kumar - Yusuf Khan
Govinda - Govinda Arun Ahuja
Jeetendra - Ravi Kapoor
John Abraham - Farhan Abraham
Johnny Lever - Badruddin Qazi
Kamal Haasan- Alwarpettai Aandavar
Kumar Gaurav - Manoj Tulli
Lucky Ali - Maqsood Mehmood Ali
Madhubala - Mumtaz Jehan Begum Dehlavi
Mahima Chaudhry - Ritu Chaudhry
Mallika Sherawat - Reema Lamba
Manoj Kumar - Hare Krishna Goswami
Nana Patekar - Vishwanath Patekar
Raj Kumar - Kulbushan Pandit
Rajesh Khanna - Jatin Khanna
Rajnikant - Sivaji Rao Gaekwad
Rekha - Bhanurekha Ganesan
Salman Khan- Abdul Rashid Salim Salman Khan
Sanjeev Kumar - Haribhai Jarivala
Shammi Kapoor - Shamsher Raj Kapoor
Shashi Kapoor – Balbir Raj Kapoor
Sunil Dutt - Balraj Dutt
Sunny Deol - Ajay Singh Deol
Tuntun : Uma Devi Khatri