SPOILER: Nathan Fillion & Guest Star Interview for Tonight’s Castle.

WARNING: This post contains spoilers for tonight’s episode of Castle.  ET recently visited the set of Castle to talk with Nathan Fillion and a guest-star about the episode, watch the video below.

“I’m the one guy who lives in a cave and doesn’t actually follow the Kardashians,” Fillion, who plays Castle on the show, admitted. “I’m told they’re petite. I know that much.”

“I don’t know what the Kardashians think,” Fillion said when asked if he believes the Kardashians will enjoy the episode. “I think they’re lovely people…I hope they enjoy it…We’re not trying to hurt anybody’s feelings.”

Hilarie Burton, who plays the Kardashian-esque character, discussed her adjustment to an atypical role for her.

“I don’t think I’ve ever played a ‘hot chick’ before,” Burton said. “I always play the quirky friend or the really angry girl.”

“I have a much higher voice during this episode,” Burton revealed as she snapped into character. “And my mannerisms are kind of different,” she added as she jerked her head to the side.