I am using wordpress. In that I want to add one of my custom rewrite rule.

I want two URL need to be work for same file.

For example

www . test . com/abc <--- At present this is implemented & working fine
www . test . com/abc.html <--- Need to add .html at back side..But in this case it appear 404 page.. I want to show same page with .html extension

Can anyone tell me? what to do for it?