Family and friends are gathering for the wedding of Robert Kennedy Jr and Curb Your Enthusiasm actress Cheryl Hines at the Kennedy compound on Cape Cod.
Kennedy's cousin Patrick Kennedy said the wedding was due to take place on Saturday afternoon at Ethel Kennedy's home in Hyannis Port.
Robert Kennedy, 60, is an environmental lawyer and activist who lives in New York.
He is the son of the late Senator Robert F Kennedy and this will be his third marriage.
Hines, 48, has been nominated twice for Emmys for her role playing Larry David's wife on the hit sitcom, Curb Your Enthusiasm.