Graffiti artists hired to work on the set of Showtime's "Homeland" have duped the popular series, painting Arabic slogans criticizing the show on walls seen in the background.

In the episode aired in the U.S. Sunday — set in a Hezbollah-run refugee camp in Lebanon but filmed in Berlin — star Claire Danes can be seen walking by slogans including ones that read "Homeland is racist" and "Homeland is a joke and it didn't make us laugh."

The group, calling itself "The Arabian Street Artists" — the name itself a tongue-in-cheek jab at the initial solicitation from Homeland producers for the set work — kept the action quiet until the episode was shown, even though it was filmed in the summer.

On Wednesday, the three — Berlin graffiti artist Stone, Heba Amin and Caram Kapp — published the details on Cairo-based Amin's website, and the images quickly went viral.

"I think this really had an impact, and we obviously struck a chord," Stone, who goes by one name, told The Associated Press on Thursday.

"From the reactions we have seen, a lot of people had not so happy feelings about this show so there is a lot of happiness coming our way right now."

"Homeland" producer Alex Gansa said he'd rather have caught the images before they made it to air, but suggested a grudging respect for the artists' work.

"As Homeland always strives to be subversive in its own right and a stimulus for conversation, we can't help but admire this act of artistic sabotage," he said in a statement provided by Showtime.

The Emmy award-winning show now in its fifth season is extremely popular, but has also been widely criticized for its depiction of Muslims, and also by the governments of Lebanon and Pakistan for its portrayals of their countries.

Still, Stone said most positive responses he has seen have actually been from the U.S., though also from the Middle East.

The three came up with the idea early this summer, when Stone was contacted by the production company looking for graffiti artists who could add authentic-looking graffiti to the film set depicting a Syrian refugee camp.

Stone said the group was initially unsure if they wanted to work on "Homeland" at all "until we got the idea we could insert our message into the show."

The artists said it was more than just a prank, they wanted to express their feelings about the show and initially considered using Arabic proverbs and slightly rewriting them with coded messages.

"The question was how can we get a message across that is not so blatant that they will immediately recognize it," he said. "But then when the actual shooting started, it was pretty clear no one would even look at it."

So they started adding their messages, which also included "Homeland is not a (TV) series"; "There is no Homeland"; "Black lives matter"; and "Homeland is watermelon" — using an Arabic expression meaning something is superficial or a joke.