Jimmy Fallon and his producer wife of 12 years, Nancy Juvonen, were spotted on Friday at the 1770 House in East Hampton a day after the late-night host’s 45th birthday.

Even though the couple was having a romantic dinner for two, we hear that when the eatery presented Fallon with a special cake, he generously shared it with strangers.

Said a witness, “It was an ice-cream cake, house-made by chef Michael Rozzi and inscribed ‘Happy Birthday Jimmy.’ ” When “surrounding tables joined in singing ‘Happy Birthday,’” “The Tonight Show” host “took a picture of the cake and shared his cake with fellow diners.”