Alicia Keys holds free private performance for sick children

SAN FRANCISCO -- For children battling life-threatening diseases and illnesses, sometimes the smallest things can brighten the spirits of both patients and their families.

Other times, it's not something small at all, it's something REALLY BIG. This week, a music superstar showed up at UCSF Benioff Children's Hospital in San Francisco.

Alicia Keys hosted a singalong for a small group of kids and their parents, then stuck around for pictures.

Veronica Coleman and her son Tucker were among those who got to attend.  Veronica shared pictures and video to Facebook, apologizing that it was so shaky, saying she was crying the whole time.

One year old Tucker has been battling cancer most of his life and spent much of his fight at UCSF Benioff.

Keys and Lenny Kravitz also teamed up for a public fundraiser called "The Concert for Kids" held at AT&T Park the same night.

If you'd like to help the cause, you can donate to UCSF Benioff and to Family House, where many of the families stay while their children are hospitalized.