This is not the first time that Rex has braved the acting world -- he made his debut during the Dublin Fringe Festival.
The steamy video shows Rex and Roz (22) embracing each other dressed only in their underwear.
The duo star as a Bonnie and Clyde-type couple in the music video for Up, from This Club's Highlife album.
The storyline follows the gun-toting duo who are forced to shoot their way out of a sticky situation and end up in bed together at their secluded hideaway.
The video, which was directed by Eoghan Kidney and produced by Tim Duggan, develops into a James Bond-style montage with graphic effects.
Rex has been studying at the Gaiety School of Acting and is set to graduate later this year. He is one of the late DJ Gerry's five children with Morah.