State space matrices in discrete state space block in Simulink

I am currently implementing a discrete state space system in Simulink using the discrete state space block. Do I need to discretize my continous system before entering it into discrete state space block or do I enter the continous state space matrices and the block has a built in c2d command.

Note I have the read the discrete state space block documentation on Matlab and couldnot find a clue.

[Raj]

Is you system time variant? I mean are the A,B,C,D matrices changing with time? I don't think you need to do any change to the matrices. You can just use them as they are.

[Marwan Wael]

No sir they are time invariant