Most people know Sarah Jessica Parker for her on-screen roles, most memorably in the HBO series, "Sex and the City."
But the actress has another passion that's close to her heart -- helping children through UNICEF.
"I am not making this up. My oldest memory is trick-or-treating with UNICEF," she said to ABC's Diane Sawyer.
Trick-or-treat for UNICEF has been going on for 56 years and began with U.S. children collecting money for European kids during World War II.
Since then, the charity has raised more than $132 million.
"It's an organization that's saved more children's lives than any other organization," Parker said about UNICEF. "A minuscule amount of money can save a child's life."
A 7-cent donation can buy crayons for a classroom; $1 can immunize a child against polio, UNICEF says.
"What UNICEF does is it goes to the children that are most in peril, countries with man-made and nature-made crises, and changes lives," Parker said.
As a child growing up in Cincinnati, Parker and her seven siblings were heavily involved with UNICEF.
Now that her son, James, is old enough to enjoy trick-or-treating, she wants him to join in the family tradition.
James will turn 4 years old on Saturday. Parker says he's psyched for Halloween but can't decide on a costume.
"He changes every 20 minutes or so. … It's now between Spiderman, Superman, Skeleton Man and Buzz Lightyear," she said.
Parker will be trick-or-treating with him on Tuesday, but she won't be in costume.
"I haven't for years. I just can't abide it. I'm so old," she said. "I'm so happy to walk around with these UNICEF boxes and with my son and try to go monitor his candy."
For more information about UNICEF or to make a donation, visit unicef.org.