JAMES MACARTHUR who played "DANNO" Det. Danny Williams in the hit 1960s series Hawaii Five-O has died at 72.

His rep said Mac died of natural causes with his family at his side.

MacArthur, born December 8 1937, was adopted by stage legend HELEN HAYES and playwright Charles MacArthur.

James began his career working for Walt Disney appearing in such films as Kidnapped, Third Man on the Mountain, Swiss Family Robinson and The Light in the Forest. 

He also costarred with Clint Eastwood in Hang’ Em High – which led directly to him being cast in the popular tropical paradise crime show "Hawaii Five-0," which aired from 1968 to 1980.

Jack Lord’s iconic catch phrase after a baddie was caught "Book ’em, Danno" became a pop culture standard.

MacArthur quit the role of McGarret’s sidekick a year before the series ended.

"Quite frankly, I grew bored," Mac said.

In a recent interview with The ENQUIRER MacArthur said he was going to guest on the new incarnation of Hawaii Five-O but alas with his sudden passing that was not meant to be.

Mac was married to actress Joyce Bulifant from 1958 to 1967, and to F Troop actress Melody Patterson from 1970 to 1975. Both unions ended in divorce.

MacArthur is survived by his wife, Helen Beth Duntz, four children and seven grandchildren.

In lieu of flowers, the family asks that contributions be made to the Helen Hayes Awards in Washington; the Helen Hayes Hospital in Nyack; the Solebury School MOM Fund in New Hope; the Palm Desert Community Presbyterian Church in Palm Desert, Calif.; and the Hawaii Theatre in Honolulu.

Church and memorial services will be held in Nyack, Palm Desert and Honolulu.

Aloha, amigo.