The 20-year-old British singer made friends with Grint after he brought him on stage for his recent gig at the University of Hertfordshire in Hatfield.
He is now set to star in his new music video as well and will play his body double.
According to UK newspaper The Sun, Sheeran said: 'When I was coming up with ideas for the Lego House video, I knew that I wanted Rupert to be in it.
'I've grown up with the Potter films and have massive respect for him as an actor. This video is going to be brilliant.'