Nick Lachey serenaded patients at a children's hospital in Los Angeles with holiday tunes during a visit last week (ends15Dec13).
The 98 Degrees star turned up at the Mattel Children's Hospital UCLA with a guitarist on Friday (13Dec13) and put on a festive-themed show for ill kids on the wards.
The singer also donned scrubs so he could sing Christmas hits for young patients who were too ill to leave their rooms.
Tweeting about his visit, he writes, "Had a great time with the kids at Mattel Children's Hospital on Friday!"
A source tells People.com, "The kids had the biggest smiles on their faces, and Nick was so touched by the strength of the children - there was not a dry eye in the room."