"My sister Jennifer ... brings an exceptional dedication to her job, her family, and her community, and has been a role model of mine for many, many years," the actor known for roles in Office Space and Sex and the City said in a statement Wednesday.
The actor goes on to say he's "extremely proud" of his sibling, who is also an Emmy-winning journalist and mother of three daughters.
On Tuesday morning, Livingston, a CBS WKBT news anchor in La Crosse, Wis., appeared on air and read an email from a viewer, who was harshly critical of her appearance.
"I was surprised indeed to witness that your physical condition hasn't improved for many years," the viewer wrote. "Surely you don't consider yourself a suitable example for this community's young people, girls in particular."
Livingston hit back with a passionate response calling the email "cruel." (See the full video below.)
"You know nothing about me but what you see on the outside," she said. "And I am much more than a number on the scale."