WhatsApp is introducing a new way to add and chat with contacts, without having to share your phone number. Usernames will launch “later this year,” in a move to make the communications platform “even more private,” allowing you to keep your phone number concealed from people who aren’t already in your contacts.

Usernames are available to reserve starting this week, giving you time to claim a specific handle you may already be using elsewhere before the WhatsApp username feature officially launches. The username launch will be rolling out gradually over the coming months, and users will be notified when the feature is available in their country.

“With over three billion people on WhatsApp a lot of names overlap, which is why we’re opening reservations early so everyone has the opportunity to select the username that matters to them,” WhatsApp said in its announcement.

You can reserve your username by heading to Settings > Account > Username in the latest version of WhatsApp on Android, or by tapping You, selecting your profile, and tapping on Create Username for iOS users. Individuals and organizations will have the option to claim their existing Instagram or Facebook handles, as long as it hasn’t been taken by another user. WhatsApp product head Alice Newton-Rex told The Verge that usernames for famous figures like celebrities and politicians have already been reserved to prevent them from being claimed — so if you share a name with a recognized public figure, you’ll have to create an alternative handle.

You can’t browse for people using their usernames, so you’ll need to know the exact username of a new contact before you can reach out to them. If you’ve already shared your phone number with WhatsApp contacts or group chats, the number will still be visible to them after you enable the username feature, so these privacy protections only apply to new conversations going forward.

WhatsApp is also introducing an “optional username key” that others will need to know before they can message you, to help you control who can reach you with a WhatsApp username if it’s made public without your consent.

Update, June 29th: Clarified how to reserve your WhatsApp username across both iOS and Android, now that the FAQ page is live.