The 29-year-old comedian smirked as he refused to answer questions about the Sky Sports presenter.
The celebrity pair reportedly hooked up after partying at London’s Groucho Club.
Whitehall was hounded by a reporter after he landed in the US, where he was asked: “Jack, can you tell me anything about Kirsty?”
The Bad Education star smirked before supressing a laugh as he made his way up an escalator.
The reporter continued to try for a response, asking, “She's a bit of a cougar, huh?” and “Are you going to see her anytime soon?” But Whitehall remained tight lipped.
Whitehall and Gallacher enjoyed a night together after heading to a flat party with stars including Caroline Flack and Matt Richardson, according to The Sun.
A source told the publication the pair’s “chemistry” had been “brewing all night”.
“They had the hots for each other,” the source said.
“When they got [to the flat party], they ramped things up and weren’t trying to hide it.
“They were kissing and being very touchy-feely before heading off for some privacy. Everybody there knew what was going on. Jack’s always had a thing for Kirsty and thinks she’s hot.”
The source finished: “Given that they are both single, they went for it. Who knows if anything serious will develop? But it’s fun for the moment.”
Standard Online has contacted representatives for Gallacher and Whitehall for comment.