You would be very clear about the understanding of the roles when you look at the 24 crafts of cinema. But in the last few years, a lot of changes have happened wherein a specialist in one craft has begun displaying his/her talent in another craft as well. Here is an example which will substantiate.
Apparently, when you think of singers you will immediately recollect names of SPB, Karthik, Hemachandra and others. If it is lyricists, you can think of Ramajogayya Sastry, Sirivennela Seetarama Sastry and others. But can you imagine that few lyricists are actually singing sensations?
Well, they are the trio of Chandrabose, Ramajogayya Sastry and Ananth Sri Ram. It is heard that they can sing like professionals. Usually, some lyricists try but they can do only for a moment. However, that is not the case with these three. Even onstage also they can sing and along with that they are good at entertaining people. Let us wait to see that happen soon.