An electronic device includes a display, one or more processors, and memory storing one or more programs configured to be executed by the one or more processors. The device can display a messaging user interface of a messaging application, the messaging user interface including: a message region including a plurality of messages between participants in a message conversation that includes three or more participants, and an affordance separate from the message region for starting a live video communication session in a live video communication application. The device can detect an input corresponding to selection of the affordance. In response to, detecting the input corresponding to selection of the affordance, the device can initiate a process for starting the live video communication session in the live video communication application, the live video communication session including the participants of the message conversation.