Revered actress Marlo Thomas is to be handed a Lifetime Achievement award by a U.S. charity organization for her public service work.

The That Girl star has been selected by the Jefferson Awards for her 20-year commitment to raising money for pediatric cancer research and her involvement with St. Jude Children's Research Hospital, which was founded by her father and comedian Danny Thomas.

And the star admits she couldn't be more proud, insisting charity work has completely changed her life.

She tells the Associated Press, "It completely stops you short. It's almost irresistible. You have to stop doing what you're doing and help."

Thomas will accept the accolade in New York City on Wednesday.