Hathaway and friends enjoyed the private celebration shrouded by white curtains within an intimate enclosure, reported Us magazine.
"There were around 40 people attending -- two long tables for a sit-down dinner with candles," a source said.
The 'Dark Knight Rises' star attended her birthday party in a Gotham-worthy getup, wearing a high-neck button-down blouse beneath a cropped jacket.
"(Anne) looked great. She got up a lot and was socializing with guests," the source added.
A-list stars at Hathaway's birthday bash included Amy Adams, her fiance Darren LeGallo and Demi Moore.