Glenn Howerton, Rob McElhenney and Charlie Day have collaborated to create Four Walls Whiskey. The producers, writers, and stars in FX’s hit sitcom 'It’s Always Sunny in Philadelphia' (which also stars Kaitlin Olson and Danny DeVito) have launched the brand to capture the spirit of Paddy’s Pub, the Irish bar the characters run in South Philadelphia and as a means of supporting the hospitality industry in the city. The main expression is called The Bartender’s Blend, and it’s an American-Irish marriage of malt Irish whiskeys with Pennsylvania Straight Rye Whiskey. There’s also an ultra-rare all-Irish Cask Strength Single Barrel Collector’s Edition which was made in pot stills and matured in ex-bourbon barrels for over 15 years.