Karaoke can bring a smile to anyone's face, especially if the singers are rookies from a pro football team. First-year Arizona Cardinals players stopped by Phoenix Children's Hospital to visit young hospital patients... and ended up singing a little Taylor Swift karaoke.

As 25 rookies made their rounds, some of them ended up in the room of a young girl named Bethany, who was recovering from appendix surgery. They piled into a room with her, blasting Swift's catchy 'I Knew You Were Trouble' as she sang along with the microphone.

The patient knew every word of the song, and looked like she was having the time of her life, with the players singing and bobbing their heads to the catchy dubstep beat. One of them even danced around with a giant stuffed puppy, while another picked up a tiny guitar, really making Bethany's day.

"It was very good. We did her backup, played some instruments, it was a good time," first-round draft pick Jonathan Cooper said after the fact.

According to the team's website, this was one of the first times the team saw each other in a non-field capacity. And with the severity of the illnesses awaiting them at the hospital, many players saw a side of their teammates they won’t see often.

“We are able to see each other outside of being competitive and being those tough guys,” defensive back Tyrann Mathieu adds. “We kinda see people break down and kinda really see people show their hearts.”

The image of big, strong football players dancing around to Taylor Swift will be a lasting memory -- not only for Bethany, but also for the Cardinals rookies.