Kissing Kit Harington was a career low for Sophie Turner.

The actress joked to “Late Night With Seth Meyers” viewers on Thursday that locking lips with her “Game of Thrones” co-star for their upcoming movie, “The Dreadful,” was “worse” than once filming a cockroach scene.

“I have to be honest,” the 29-year-old said. “It was bad.”

Turner and Harington played onscreen half-siblings Sansa Stark and Jon Snow in the HBO series between 2011 and 2019.

Turner “immediately … thought of” the actor, 38, when she “got this script for this amazing Gothic horror” she was set to produce.

“I sent the script to Kit,” she remembered. “He kind of sent me a message back, like, ‘Yeah, I’d love to, but this is gonna be really f–king weird.’”

While Turner initially didn’t know what Harington was “talking about,” she realized their characters shared many intimate scenes.

“Kiss, kiss, sex, kiss, sex,” the “Trust” star recalled thinking as she flipped through the script. “I was like, ‘Oh, shoot. That’s my brother.’ But it was such a good script that he was like, ‘We kind of have to do it.’”

Although the pair “put it out of [their] minds,” they were both “retching” filming their first kissing scene.

Turner quipped that the “really bad moment” in her acting journey was “vile.”

Harington, notably, married their fellow “Game of Thrones” cast member Rose Leslie in 2018, and the duo share two children.

The couple have kept their son, 4, and daughter, 2, out of the spotlight, just as Turner and her ex-husband, Joe Jonas, have done with their little ones.

The former couple, who were married from 2019 to 2024, are the parents of daughter Willa, 5, and daughter Delphine, 3.

After splitting from the Jonas Brother member, Turner moved on with aristocrat Peregrine “Perry” Pearson.

Elsewhere in Thursday’s interview, the Emmy nominee dished on an A-list couple who ended their engagement over her “accidental” flirting.

Turner waved at an actor she didn’t recognize for her friend’s sake, only to be told by the man’s partner — a “famous actress” in her own right — to “stop f–king flirting with [her] fiancé.”

The “Staircase” star revealed, “Turns out, they broke their engagement off that night because of my [wave]. I didn’t realize I held this power.”

Social media sleuths believe the exes, whom Turner did not name to avoid getting “in trouble,” are Emma Roberts and Evan Peters.

The “American Horror Story” stars, who had a tumultuous relationship on and off from 2012 to 2019, were present at the San Diego Comic-Con afterparty where Turner said the interaction took place.

Roberts, 34, was photographed crying afterward.

Reps for Roberts and Peters have yet to respond to Page Six’s requests for comment.