The Clooney Foundation for Justice made the announcement on Tuesday and will soon share the further details, reported Entertainment Weekly.
The SPLC stated the move is a response to the violence that erupted at the white nationalist rally on August 12 in Charlottesville, Virginia that left one protester dead.
"We are proud to support the Southern Poverty Law Center in its efforts to prevent violent extremism in the United States. What happened in Charlottesville, and what is happening in communities across our country, demands our collective engagement to stand up to hate," the Clooneys said in a joint statement.
The SPLC currently tracks more than 1,600 extremist hate groups operating in the US.