A telepath I think in the 70 or 80 is keeping his ability hidden hears aliens planning to take over the planet. He tells the authoritys, who help him

[John2814]

He works with the government but is afraid that they will confin him after they defeated the aliens but he thinks they are the bigger threat so he comes out of hidden to tell the government.

 

[wwsierra]

I know of a similar novel: “Three to Conquer” by Eric Frank Russell. However, it may not be the one you are trying to find. This was written in the 50's as part of an ACE SF double -- and was a story taking place in the near future so most of the visions of the future aren't too accurate . The character can read minds and does his best to hide the fact. On a road trip he answers a cry for help and in his searching to help the police realizes he has come across the fact that three spacemen who were on a secret mission to Venus have returned with aliens in control of their minds. Even if this isn't what you are looking for, you might find it a good read. I still re-read it every several years, as I like the story and the writing style.

Hope this helps,
Walt