By Maureen Lee Lenker
September 05, 2018 at 03:42 PM EDT
Paul Archuleta/Getty Images

Christopher Lawford, an actor and member of the Kennedy family, has died. He was 63.

Lawford’s death was confirmed by his cousin Kerry Kennedy on Twitter. She wrote, “We mourn the loss of my cousin Christopher Lawford, Rest in Peace. Pictured here with our family at the 2004 Democratic Convention and with his wonderful son, David.”

Kennedy provided no further details on Lawford’s cause of death, and Lawford’s representatives declined to provide additional information.

Lawford was an actor with over 40 credits to his name, including Terminator 3: Rise of the Machines and Thirteen Days — a film about the Cuban Missile Crisis that featured his uncles John and Robert Kennedy as characters. Lawford had a robust career on television, guesting on a wide range of series, including Frasier, Chicago Hope, The O.C., All My Children, and General Hospital. He was also a correspondent on entertainment news program EXTRA.

He was the son of actor and Rat Pack member Peter Lawford (Ocean’s 11) and Patricia Kennedy, sister of President John F. Kennedy and Senator Robert Kennedy.

Christopher Lawford was born on March 29, 1955 in Santa Monica, California. In addition to his career as an actor, he also was active in politics, working with the Democratic National Committee, the United Nations, the White House Office on Drug Control Policy, the World Health Organization, and the Canadian Center on Substance Abuse.

Lawford struggled publicly with substance abuse and addiction in the 1970s and ’80s, which he later funneled into his work as an activist. He eventually founded the Global Recovery Initiative, to help shape social and cultural attitudes toward addiction and create more pathways for recovery. He also authored a book about recovery titled Symptoms of Withdrawal: A Memoir of Snapshots and Redemption, Moments of Clarity.

In 2009, Lawford was appointed to the California Public Health Advisory Committee. He was named Goodwill Ambassador for the United Nations Office on Drugs and Crime in 2011.

Lawford is survived by his second wife, Mercedes Miller, and his children, two sons and a daughter, from his first marriage to Jeannie Olsson.