Laid off. Should I tell interviewer ?

I was laid off last month, and got two months seperation package. If I have interview chance now, if interviewer don't ask why I want to apply for this position, should I tell them the reason is because I was laid off recently?
Also, in generally, should I just tell interviewer that I am unemployed now, or avoid to start this topic? Pls share your experience, thanks a lot!