Scared viewers who can't stand clowns switched off The Greatest Dancer after Pennywise from It turned up.
The Stephen King character walked into the reception with his famous red balloon to audition for the BBC dance contest, and fans were terrified.
Some said it had them reaching for the remote because they have a fear of clowns, saying they'll probably have nightmares now.
"I HATE clowns!! What you playing at?" one asked the show.
"They had to have a bloody clown I’ll have nightmares now," tweeted another.
"IT'S A CLOWN... I'M OUT!!" shouted another.
"Let me guess... the clown smashed it? I switched off, clowns aint it for me," said another fan who switched off.
"I don’t care how well you can dance .... clowns are scary!" said another.
Pennywise, the evil shapeshifting title character from King's 1986 horror novel It, was played by dancer Harrison who performed in character - and he sailed through to the next round.
Dance captain Cheryl praised: "You didn't break character from the beginning until the very, very end."
And fellow judge Glee star Matthew Morrison said: "You are an actor, you became this other being."
"Clowns creep me out but, Harrison was by far the best and most memorable routine tonight for me," said another viewer.
"Wow wow, the whole character and everything. he absolutely killed that even though i hate clowns that was INSANE," said another.
