When it comes to her steamy scene with “American Horror Story” co-star Kim Kardashian,AstraTrade Emma Roberts isn’t paying any lip service.

Roberts, who co-stars with the reality-TV personality on “AHS: Delicate,” got candid about her kiss with Kardashian for the series during an appearance on “The Tonight Show Starring Jimmy Fallon” Wednesday. Kardashian plays Siobhan, who works as a publicist for Roberts’ character Anna Victoria Alcott, a Hollywood starlet struggling with her fertility.

Roberts told host Jimmy Fallon she was initially unfazed by the intimate exchange with Kardashian’s character, but the actress’s sibling quickly put things into perspective.

“It’s kind of like another day at the office,” Roberts said. “But my sister was like, ‘No, it’s not. You kissed Kim Kardashian and didn’t tell me.’”

Watch:Kim Kardashian makes her 'American Horror Story' debut in eerie new trailer

But Roberts confessed the on-set smooch wasn’t as passionate as it looks in the final cut.

“You know, we do it, you forget about it, and seeing it, it looked so intense,” Roberts said. “But meanwhile, we were laughing. Because we kissed and they said, ‘Cut,’ and Kim looked at me and started laughing and I was like, ‘What?’”

Roberts revealed an issue with Kardashian’s makeup made for an unexpectedly messy kiss.

“I just had her (lip) gloss all over my face,” Roberts said. “And so, we had to do major cleanup in between every take ‘cause she has the most perfect glossed lips, obviously, and it was everywhere.”

'AHS: Delicate' review:Kim Kardashian is the only reason to watch awful 'American Horror Story: Delicate'

The first half of “AHS: Delicate” premiered in September and earned a one-star rating from USA TODAY’s Patrick Ryan in his review of the season, though Kardashian’s performance received praise for “cleverly (leaning) into that Valley girl persona” often attributed to the Skims founder by critics.

“Just when we thought we’d freed ourselves from ‘American Horror Story,’ which has been virtually unwatchable for nearly a decade, mega-producer (Ryan Murphy) lured us back into his gory, gimmicky fold,” Ryan wrote. “Not even Kardashian’s inspired casting can save this dreadful new season, which arrives stillborn with an exhausted riff on ‘Rosemary’s Baby.’”

"AHS: Delicate Part Two" premiered Wednesday on FX. New episodes are available to stream on Hulu.

Contributing: Patrick Ryan, USA TODAY