Colm Meaney is joining The Gang on their Irish exploits in the upcoming Season 15 of It's Always Sunny in Philadelphia!

A new teaser trailer for the highly-anticipated Season 15 of 'It's Always Sunny in Philadelphia' was released today, November 10, and revealed a huge surprise - Irish actor Colm Meaney has a guest role!

"We're gonna go on vacation," Mac, played by Rob McElhenney, says in the trailer.

"Ireland, baby!" Dee, played by Kaitlin Olson, says.

In another scene, Mac tells Charlie, played by Charlie Day, "You're not as Irish as I am," to which Charlie replies, "I can be as Irish as you are!"

Later in the clip, we see Meaney alongside Charlie who says, "This dude is like the Irish version of me. We're into, like, a lot of the same stuff. Ghouls, and cheese, and ... ghouls."

Back in August, posted a casting call for a "Danny DeVito Double" ahead of an 'Always Sunny' shoot in Dublin.

In the weeks after the Irish casting call was posted, the show’s cast began sharing pictures from what could only be Ireland on their social media feeds.

Though they didn’t explicitly say where they were, both Olson and McElhenney, who are married in real life, added shamrock emojis into their captions on Instagram which may have been snapped at the Cliffs of Moher in Co Clare.

On November 3, it was announced that Season 15 of 'It's Always Sunny in Philadelphia' would, finally, be premiering on December 1. A synopsis of the new season, which proved that the gang would be getting up to some Irish shenanigans, reads:

"10:00 PM…

On a Wednesday…

In Ireland.

The record-breaking 15th season of It’s Always Sunny in Philadelphia is its most ambitious yet. In the seismic wake of Covid-19 and all things 2020, The Gang stands at a crossroads in this strange new world. The rules are changing quicker than anyone can keep up with, despite herculean efforts from “Mac” (Rob McElhenney), “Charlie” (Charlie Day), “Dennis” (Glenn Howerton), “Dee” (Kaitlin Olson) and “Frank” (Danny DeVito) to continue business as usual. Now, they must face the music and decide who they’ll become in the cultural upheaval that is 2021. Across the span of eight episodes — and the Atlantic Ocean — we find them answer in a way only they could think to.

Like a fine Irish whiskey, Sunny’s distinct flavor has gotten richer and intensified through the years. First barreled in 2005, the show has become a landmark for dark comedy and American satire, uniting the most devoted of fans from all over the country and abroad, and this monumental 15th season is truly one to crack open and celebrate.

Continuing to deliver some of the hardest laughs on television while tackling society’s most pressing issues, Sunny turns its fearless focus both outward and inward: to a national and international level but also to a deeply personal level. This is a season that sees The Gang try to exploit pandemic aid, sidestep cancel culture, evade criminal justice, reflect on their origins, and reconcile their identities and homeland roots."

Starring Rob McElhenney, Charlie Day, Glenn Howerton, Kaitlin Olson, and Danny DeVito, It's Always Sunny in Philadelphia follows “The Gang” and their despicable exploits centered around their unsuccessful Irish bar Paddy’s Pub in South Philadelphia.

The show, which began airing on FX in the US in 2005 and now runs on FXX, has become the longest-running live-action comedy series in American television history.

Rife with Irish American and Catholic undertones, the show has several St. Patrick’s Day-themed episodes, which heavily - and humorously - rely on the worst Irish and Irish American stereotypes.