Should we tell our potential landlady that we have a cat or try to hide her?

I’m about to sign a lease on an apartment, but the lease they sent says we don’t have a cat, which we do. We said so on our application so we assumed it was okay. If we just go ahead and sign the lease she would never know we had her, but if she found out we could get evicted. How should we tell her something that might mean we have to continue looking for an apartment in this crazy market?