WhatsApp ‘Private Reply’ feature has been added in the latest version(2.18.335) of WhatsApp Beta in Android. There were reports last year which show that WhatsApp is working on Private Reply Feature and for sometime it is showed up on the Beta version of WhatsApp on Windows.
It has taken almost a year to reveal this feature on WhatsApp by the way, at this time this feature is only available on WhatsApp Beta on Android. It is expected that this feature will soon available on the stable version of WhatsApp.
According to the Reports of WABetaInfo, The feature is called ‘Reply Privately’. It allows people to reply privately to a message received in the WhatsApp group. When the user selects a contact for options and taps on ‘reply privately’ option, WhatsApp will automatically open a private window with the contact. The reports are showing that this feature can also work for old messages as well. The feature apparently works for closed groups as well. WABetaInfo informs that the beta version 2.18.335 has bugs and when you try to delete a media in the chat.