Taylor Swift has a heart as big as her trophy collection. The '22' singer, who's hard at work on her Red tour with Ed Sheeran, took time out of her hectic promo schedule to visit a Philadelphia children's hospital -- and she didn't tell a soul about it.

Swift never mentioned the trip, but her pal Ryan Seacrest, who works with the Children's Hospital in Philadelphia, tweeted about it, linking to the above photo set.

The Children's Hospital in Philadelphia is actually partnered up with the Ryan Seacrest Foundation, which provides a special radio station just for the hospital. The young patients are able to conduct interviews, play their favorite songs and escape reality for a while.

Swift regularly makes charitable trips, earning her the Nickelodeon Big Help Award in 2012 and getting herself named "Most Charitable Celebrity" by DoSomething.org, but she never brags about it ... which implies that her motives for her good deeds are pretty pure since she's not seeking PR from them.

Just before embarking on her Red tour -- her biggest yet -- Cambio reports that Swift stopped at the Omaha Children's Hospital + Medical Center to visit a young fan with cancer.

Kudos to T-Swizzle for her awesome deeds, and our best wishes to the patients!