People can now launch live broadcasts on Twitter-owned Periscope directly from the Twitter mobile app on iOS and Android. Doing so is as simple as heading to the compose screen, tapping the camera icon, and selecting the Live option.

From Twitter:

Once you tap the button, you'll be taken directly to the Periscope app's live broadcast screen, where you'll be asked to title your broadcast and actually initiate the stream itself. Previously, you'd need to head to the Periscope app in order to start a stream.