According to FemaleFirst, the 29-year-old actor was seen last weekend hanging out with Bruce Willis’ 19-year-old daughter, Rumer, at a club in New York.
A source at the club stated, "Josh and Rumer were hanging out all night. They definitely seemed to be getting pretty cosy!"
After an evening of drinking, dancing and laughing together, the couple left the club at the same time.
Hartnett, who has dated Kirsten Dunst, Scarlett Johansson and Rihanna, admitted that he has a slight preference for British ladies.
Willis used to date Benji Madden, from the group Good Charlotte, and actor Ravi Gavron.