WhatsApp has announced a new "Chat Lock" service, which provides additional protection for your most important and private conversations.

The Chat Lock feature moves a thread of messages from your inbox to its own folder, which can only be opened with your device's password or biometrics such as your fingerprint. This feature also automatically hides the content of that chat from notifications.

We think this feature is great for people who occasionally have to share their phone with a family member, or when your phone happens to be in someone else's hands just as you receive a very private message. You can lock a chat by tapping on the name of a one-on-one or group chat and selecting the lock option. To reveal these chats, swipe down slowly in your inbox and enter your phone password or biometrics.

Over the next few months, we'll be adding more options to Chat Lock, including locking companion devices and creating a custom password for your chats so you can use a unique password different from your phone password.