The 36-year-old "Rick and Morty" star was eating at The Black Ant in the East Village when a man who appeared to be drunk was turned away as he tried to get a table at the restaurant at about 11.30 P.M.
Onlookers told the New York Post's gossip column Page Six he launched into an "unhinged tailspin" when informed the restaurant was closing, and began arguing with employees and several customers, when Spencer and her dinner partner, Jan Phillip Mueller, intervened.
Despite initial reports stating Spencer was slashed in the right forearm while Mueller was caught in the back with a knife, and both were taken to the nearby Bellevue Hospital for treatment, Kelsey told People she "was not slashed" during the incident.
"There are elements of truth to the story but Spencer was not slashed; she is fine," the actor confirmed.
"While trying to intervene in an altercation the perpetrator struck a victim in the right lower back, causing a laceration. The complainant was removed to Bellevue Hospital. No arrests have been made," a spokesperson for the New York Police Department added.