It's Always Sunny in Philadelphia returned to FXX last week for its twelfth season. The premiere, the first featuring actual footage shot in Philadelphia in two season, was the network's most-watched original telecast ever, according to a release. FXX is the sister network of FX, where It's Always Sunny orginated. It focuses mostly on comedy.

Dubbed "The Gang Turns Black," (read our recap) the musical episode features the Dee (Kaitlyn Olson), Mac (Rob McElhenney), Dennis (Glenn Howerton), Charlie (Charlie Day), and Frank (Danny DeVito) waking one morning to find that they have turned into African-Americans after suffering an electrical shock while watching The Wiz. As a result, the Gang must learn "the rules" for being black in America, and find a way to return to their original, white selves.

The episode was a shocking one, complete with Philadelphia police graphically gunning down a young African-American boy — Charlie's black counterpart, played by AJ Hudson — on 10th and Market. In a review of the episode, the AV Club called that moment "a punchline that's a punch in the stomach."

As shows age, they tend to lose viewership, but "The Gang Turns Black" reverses the trend. The episode attracted 1.41 million total viewers for its Jan. 4 premiere — a 5 percent increase over the season 11 premiere, "Chardee MacDennis 2: Electric Boogaloo." The premiere also represents a 16 percent increase in viewership over the season 11 average.

Additionally, among adults aged 18 to 49, "The Gang Turns Black" saw a 7 percent increase in viewership over the season 11 premiere, with 1.14 million viewers in that age bracket for season 12 versus 981,000 viewers for season 11.

It's Always Sunny airs its next episode, "The Gang Goes to a Waterpark," on Wednesday, Jan. 11 at 10 p.m. on FXX. In that episode, the gang heads to a waterpark where Frank and Charlie attempt to ride every ride, and Mac and Dee and stuck in a waterslide.