Spirits were high at the Memorial Sloan-Kettering Cancer Center on Saturday (March 22) when superstar Taylor Swift helped light up sick kids' faces with a visit.

The singer spent the day hanging out with children and teens affected by cancer, and her positive demeanor and compassionate spirit left a mark on those she visited -- and it's safe to assume the feeling was mutual.

Throughout her time at the cancer center, Swift posed for photos with fans and video chatted with family members of the kids. One girl named Lindsey took to Twitter after Swift video chatted with her while visiting her tiny cousin.

Another lucky girl, Shelby, who is diagnosed with very severe Aplastic Anemia, was able to hang out with the 'Everything Has Changed' singer. In fact, Swift extended her planned one-hour visit on one floor of the hospital to 4.5, proving that the kids had a great impact on her.

"We are still in awe, Taylor Swift is a class act all around, she was so sweet, compassionate, asked US questions, got on Skype with my other daughter, stayed in our room and talked with us and was completely down to earth," Shelby's mom writes on Facebook. "She hung out with us for at least 15-20 minutes. She was 'scheduled' to be on our floor for 1 hour, but was here for 4.5 hours instead. Thank you Taylor, you are a beautiful woman inside and out!!"

Country music fans know that this is somewhat of a regular occurrence in the singer's life. Swift has been very involved in visiting sick kids throughout her career, and even wrote a song called 'Ronan' about a little boy's lost battle with cancer, with the proceeds from the single donated to a childhood cancer charity.