Cape Town - YouTube vlogger Caspar Lee - who has South African roots - recently invited his friend Ed Sheeran over to do the brain freeze challenge.
The brain freeze challenge involves getting your body ice cold in a variety of ways and Caspar has done it quite a few times on his channel.
In this video, Caspar gets into a super cold bath and stays there until Ed answers a question about 2016 correctly.
ICYMI: Ed took a year-long break in 2016 and stayed away from social media and the spotlight as a whole.
See Caspar and Ed's brain freeze challenge here: