Source: ec_wife/Twitter
A new test Facebook is running allows some of its users to watch their Instagram stories on the main app. You'll be able to differentiate between Facebook and Instagram stories by the colours around the profile photo. Facebook stories will have blue circles, while Instagram stories will have the pink and orange hue of the app's icon.
Facebook emphasizes that only your Instagram followers who have linked their Facebook accounts (and who initially can see your stories) will see this new option on Facebook. But they will need to opt into this setting. Facebook is doing a "limited test," with a company spokesperson confirming the feature "respects all existing privacy settings," and that Instagram users who want to keep their stories off of Facebook altogether can do so
Source: The Verge