Watch: Homeless man serenades woman who bought him food

HOUSTON -- A Houston woman's random act of kindness turns into an emotional moment she never expected.

Cristala Poole set out to pay it forward 35 times to celebrate her 35th birthday. One of those kind acts was to feed a homeless person.

and when she did, the homeless man, Maurice, thanked her by serenading her with a sweet rendition of happy birthday. She posted the video Maurice singing and their moment has gone viral.