Scarlett Johansson reportedly kissed Colin Jost at a 'Saturday Night Live' after-party at the weekend

An eyewitness said: "Scarlett and Colin were making out at the bar at the 'SNL' season finale party at 30 Rock ... They would make out a bit, then go back to talking.

"They were at the bar in front of everyone ... they made out at least twice ... Then they went back to talking and hanging with other people."

The 'Ghost in the Shell' actress - who is currently in the midst of divorcing her second husband, French journalist Romain Dauriac - apparently made no attempt to keep her interest in Colin a secret.

Another source told the New York Post newspaper's Page Six column:

"Scarlett and Colin were flirting and canoodling in full view of everyone at the after-party, including the 'SNL' cast and crew. They were laughing and seemed to really hit it off."

Meanwhile, Scarlett - who has a two-year-old daughter called Rose with her estranged husband - admitted earlier this year that she doesn't consider monogamy to be "natural".

The Hollywood star, who was previously married to actor Ryan Reynolds from 2008 until 2011, said: "I think the idea of marriage is very romantic; it's a beautiful idea. And the practice of it can be a very beautiful thing."

But Scarlett also admitted that being faithful to one partner over a prolonged period of time requires a lot of "work".

She said: "I don't think it's natural to be a monogamous person. I might be skewered for that, but I think it's work. It's a lot of work."