We all know ‘Crazy’ Mohan penned the dialogue for “MMKR”. What was his other contribution (not quite noticeable though) in the masterpiece?

He stood in the position of one of the Kamal Haasans in scenes involving two Kamal Haasans in the same shot (filmed using masking technique).
Ref: http://www.crazymohan.com/kamalmainframe14.htm
Note: Please select the above blank lines for the answer.