Though Neil Patrick Harris has had an acting career for several decades now, he admitted that he recently got nervous around one actress on the set of FX's American Horror Story: Freak Show.

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Harris revealed on Twitter Monday that he was "super nervous" around AHS star Jessica Lange while appearing on the show.

"[I keep] forgetting my lines and overthinking it," Harris admitted. "So while it was fun to do creatively, I kind of never wanted to act again while it was happening."

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This wasn't due to the quality of the writing, however.

"Not because the content was bad," he noted. "Acting is hard - you have to become another person and through that, you become insecure as that person with people that all seem to know each other."

He admitted that he felt like "the new kid at school" on the American Horror Story set.

"I arrived having done a lot of things in my life but arrived not knowing the crew and not knowing these actors who I love."

Harris is set to play a "chameleon salesman" in episodes 11 and 12 of Freak Show. The full extent of his role is not known but it is obviously a guest spot.

With Lange leaving American Horror Story after Freak Show and Sarah Paulson moving to Ryan Murphy's other project American Crime Story, they will be looking for actors to fill those spots. Could Harris join season 5 as a regular now that he's not tied to CBS's How I Met Your Mother? Only time will tell, though based on his comments he might not want to, ultimately.

American Horror Story: Freak Show airs Wednesdays at 10 p.m. ET/PT on FX.

Watch the promo for the next episode of American Horror Story here:

Tags: American Horror Story television fx