For example, Katrina was pretty much nothing till Race happened. So she didn't mind playing second fiddle to Bipasha. Same with Priyanka in Aitraaz. And then we have Madhuri and Rani who played second fiddles when their career was almost over.
If someone never played second fiddle, it has to be Aishwarya. In her very first film she was the main lead where Tabu was second lead. And till her last film she played only lead roles.
I don't think it has anything to do with insecurity. I'm sure if any actor had to choose between main lead or second lead, they will obviously choose main lead. If you have no good offers as main lead, THEN one would be forced to play second fiddles.
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