What is the difference between a reel and a real star?

Reel Stars Vs Real Stars in Biopic movies

MS Dhoni:The untold story–Ms Dhoni and Sushant Singh Rajput

2.Sarbjit–Sarbjit Singh and Randeep Hooda

3.Paan Singh Tomar–Paan Singh Tomar and Irfan Khan

4.Bhaag Milkha Bhaag–Milkha Singh and Farhan Aktar

5.Shahid–Shahid Azmi and Rajkumar Rao

6.Mary Kom–Mary Kom and Priyanka Chopra

7.Guru–Dhirubhai Ambani and Abhishek Bachchan

8.The Legend of Bhagat Singh–Bhagat Singh and Ajay Devgan

9.The Dirty Picture–Silk Smitha and Vidya Balan

10.Bandit Queen–Phoolan Devi and Seema Biswas