Two of Ireland's sporting icons have been drawn into a nasty Twitter battle.
In the red corner is WWE star Dublin-born Sheamus, standing six foot four and weighing 270 pounds.
In the blue corner is UFC contender, also Dublin-born, Conor McGregor at just 5 foot 9 inches and 146 pounds.
McGregor kicked it off by saying in an interview with Sports Illustrated that he could whup Sheamus's butt if the two ever met.
Sheamus did not take it lying down and immediately responded on twitter.
Back and forth it went. As the saying goes, it is not the size of the dog in the fight but the size of the fight in the dog. While they look a mismatch, McGregor might just shade it.
Here is their Twitter standoff: