And while his predecessor as Munster captain, Paul O'Connell, was playing in the 2008 Heineken Cup final when the sides last met, O'Mahony was in the stands as a supporter.
"I was at the 2008 final in the Millennium (Stadium) and that was obviously a good day out. I've followed Munster the whole way up, so I've seen them (Toulouse) a couple of times but in the flesh this time now!," explained the Corkman.
"Toulouse coming to Thomond Park for the first time at half one on Saturday in the quarter-final of the Heineken Cup - it doesn't get much better than that.
"Whether you're a player or a fan it's going to be an unbelievable day out, so I think everyone's looking forward to it.
"They've a huge back row and they're very dynamic as well for such big men, so we're preparing for their best team to come over.
"Regardless of who that is, it's going to be a quality side. We're going to have to certainly play the best game we've played all year to put ourselves in a position to win the game."
Along with O'Connell and O'Mahony, Conor Murray has first hand experience of playing against some of the Toulouse players heaving featured for Ireland against France last month.
"You just have to look at the amount of lads they had playing for the French team and how well they played in the Six Nations at times," said the Limerick-born scrum half.
"They're a typically French team that will try a lot of things and sometimes they come off and look spectacular. So, early on, we have to be really aware of that sort of stuff and make sure we don't give them a soft opening into the game."
Saturday's game kicks pits two-time Heineken Cup winners Munster against four-time champions Toulouse in the fifth European meeting of these great sides.
Three of the previous clashes were played in France and the most recent at the Millennium Stadium in 2008 when Munster claimed their second European title with a tense 16-13 win.
"It surprises me that they've never visited Thomond Park so it will be a great occasion," admitted current Munster head coach Rob Penney.
"It's going to be a special day having one of the teams certainly with a great history in the Heineken Cup and worthy champions that they've been four times. Us hosting them here is going to be a great day."
The French giants have a 'behemoth' pack and an extremely dangerous back-line with Penney acutely aware of the quality his charges will be up against.
"We just can't be loose with the ball, full stop. I think everyone realises the threats that Toulouse have across the park and on the bench so no matter what combination they put together it doesn't matter.
"At one stage of the game they'll be rolling people off the bench no doubt and (they are) just magnificent athletes that are blessed with a rugby talent.
"So we just need to do our best to keep the ball away from them, particularly in those fragmented phase-type plays that they seem to excel in," added the New Zealander.