Using google 2factor authentication with Private Key

I am having a AWS Linux server, & I am planning to use the 2 Factor authentication. I am having the following thing in mind:

Factor 1) SSH Key Factor 2) Google Authenticator

But on blogs and stuff i read Two-factor authentication works with passwords only. When you authenticate with your key, PAM is bypassed and no verification code is asked.

Is this possible using a Private_Key + Google Authenticator ?