Privacy Messenger

What’s the use of having a PIN-lockable messenger app if someone can force you to unlock the app for them, right? Well, this messenger lets you create two PINs — one is your real one, which unlocks all the private messages you want nobody seeing, the other is just a “guest PIN”, which lets the app work like a normal messenger, but hides your private conversations.

Source: Privacy Messenger – Android Apps on Google Play