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:

DEBATE: @UFC's @TheNotoriousMMA Vs. @WWESheamus Tweet us who wins & why! pic.twitter.com/wqCoiyDWkV

— SI Now (@SInowLIVE) November 21, 2014

ok @SInowLIVE @ufc @TheNotoriousMMA, Conor wins. I don't hit featherweights or shoeshine boys. Mouth off to @BrockLesnar fella, I'm injured.

— Sheamus (@WWESheamus) November 21, 2014

@WWESheamus, @BrockLesnar fought PURE, phoney. Me and Brock Vs You and any shmuck of your choice. #CelticPhoney #TagTeam @JRsBBQ @WWE @UFC

— Conor McGregor (@TheNotoriousMMA) November 21, 2014

Had bigger dumps after a salad @TheNotoriousMMA lad. U can hold @BrockLesnar's @WWE title while the big boys duke-it-out. Win @ufc title 1st

— Sheamus (@WWESheamus) November 21, 2014

@WWESheamus @BrockLesnar @WWE @ufc Careful now scaldy, you will wake up with no teeth and your nose on my mantle. #CelticPhoney #NeverFought

— Conor McGregor (@TheNotoriousMMA) November 21, 2014

Phoney? @TheNotoriousMMA @BrockLesnar @WWE @ufc haha that last lad you 'knocked-out' went down on the breeze of a punch... #NeverConnected

— Sheamus (@WWESheamus) November 21, 2014

@WWESheamus @BrockLesnar @WWE 'Never connected' sounds more like your game. You wear ball stranglers and slap mens asses for a living.

— Conor McGregor (@TheNotoriousMMA) November 21, 2014

Whereas you talk for a living son & we all know who's ass @TheNotoriousMMA is kissing nightly. #LittleManBigChip

— Sheamus (@WWESheamus) November 21, 2014

@WWESheamus I'll whoop you at your own game, then we can toast a whiskey and talk about true fighting. Always remember #UFCAsRealAsItGets

— Conor McGregor (@TheNotoriousMMA) November 21, 2014

Whiskey in Dublin this Christmas @TheNotoriousMMA. Shirts on the deck, back-to-back, and we'll fight everyone. #TraditionalIrishChristmas

— Sheamus (@WWESheamus) November 21, 2014