Jennifer Lopez celebrates her birthday this week, but it was still all work for her today on the set of her latest movie, Back Up Plan, in NYC.

JLo started shooting scenes for the movie last week and was even spotted on set with her adorable kids.

Today, however, Marc Antony must have been on daddy duty as Jennifer showed up wearing her sweats, ready for a hard day’s work in the hot summer sunshine.

See more pictures of Jennifer Lopez in the gallery below…