Instagram Gives You The Option To Share IGTV Content In Your Instagram Story
You can share an IGTV video by tapping the paper airplane icon at the bottom left of the video that you want to share and then clicking "Add video to your story." This will generate a thumbnail preview of the video in your Instagram Story. It looks similar to how it looks when you share a Story that you’re mentioned in, but also includes the title of the video and the length of it. When someone clicks on the thumbnail preview, it will take them to the full version of the video in the IGTV section of app.
In other news regarding Instagram Stories, the photo/video sharing app is currently testing a new ad type called Promote For Stories.