Roberts will be among the starry presenters during the three-hour show, which will be televised by CBS.
Also announced on May 22 were the stars presenting awards for the best of the 2005-06 Broadway season: Ralph Fiennes, Eric McCormack, Cynthia Nixon, Martin Short, Alfre Woodard and Anna Paquin.
Tony winners Natasha Richardson, Liev Schreiber and Phylicia Rashad announced the Tony nominees on May 16 in New York.
A host for the awards show has not been announced yet.
The Antoinette Perry Tony Awards, founded in 1947 by the American Theatre Wing, are presented by the Wing and the League of American Theatres and Producers.