AceShowbiz - Neil Patrick Harris has paid tribute to James B. Sikking after his death. The actor, who played James' on-screen son on the ABC medical sitcom "Doogie Howser, M.D.", shared their memories in an Instagram post shared on Monday, July 15.

Sharing a picture of his late co-star, the 51-year-old wrote, "Jim Sikking played my dad in Doogie Howser, MD, and was one of the kindest, wisest, funniest, and most generous people I've ever known." He also called the later star "a true professional."

"He treated everyone with respect, taught me countless lessons, yet always had a spark of mischief in his eyes. It was an absolute honor to be his son," Neil added. "My condolences to his actual family for their loss."

James passed away at the age of 90 on Saturday. His publicist, Cynthia Synder, revealed that the Hill Street Blues actor died "peacefully at his Los Angeles home surrounded by family."

"In a remarkable career, Sikking's wonderfully exciting face gave us drama, comedy, tragedy and hilarious farse," Cynthia said in a statement. "His career spanned over six decades in television, film and on stage."

The cause of death was dementia. James is survived by his wife of 61 years, Florine, his son Andrew, daughter Dr. Emily Sikking (Mallory 'Chip' Milam), as well as four grandchildren.

James was best knwon for playing Lt. Howard Hunter, the leader of the precinct's Emergency Action Team, on "Hill Street Blues" from 1981 to 1987. He also appeared on shows in the 1970s, including "Mission: Impossible," "M.A.S.H.", "Hawaii Five-O", "Charlie's Angels" and "Little House on the Prairie".

Of working with James on "Doogie Howser, M.D.", Neil told USA TODAY in 2019, "I look back on that with fondness." He added, "That was a very remarkably wonderful chapter for somebody who had never really been in the entertainment business before."