Neil Patrick Harris has described James B. Sikking as "one of the kindest, wisest, funniest, and most generous people" he's ever met.

The 51-year-old star has paid tribute to the late actor - who played his on-screen dad Dr. David Howser in almost 100 episodes of 'Doogie Howser, M.D.' - following his death aged 90 after a battle with dementia.

He wrote on Instagram: "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."

The 'How I Met Your Mother' star hailed Sikking as someone who "treated everyone with respect" while keeping a "spark of mischief".

He continued: "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. My condolences to his actual family for their loss. #RIP"

Neil's 'Uncoupled' co-star Emerson Brooks offered some words of support in response to his moving tribute.

He commented: "May his memory be a blessing. Condolences to his family."

Referencing the recent deaths of the likes of Richard Simmons, Shelley Duvall and Shannen Doherty, he added: "Losing so many legends. It’s been a rough month for us 1970s kids."

Sikking died over the weekend, with the tragic news confirmed by his publicist Cynthia Synder on Sunday (14.07.24) evening.

She told Variety: "In a remarkable career, Sikking’s wonderfully exciting face gave us drama, comedy, tragedy and hilarious farce.

"His career spanned over six decades in television, film and on stage."

The TV star is survived by his wife Florine Sikking - a cookbook author whom he married in 1962 - and their three children.

James began his television career with guest appearances on hit shows like 'Perry Mason', 'General Hospital' and 'The Fugitive' and one of his earliest appearances was a small role in the 1968 film 'Charro!' alongside Elvis Presley.

In the early 1980s, he landed his signature role on the serial police procedural show ‘Hill Street Blues' , which he played over the course of six years.

Following this, he joined the cast of 'Doogie Howser, M.D', where he played the father of the titular character (Neil Patrick Harris) and remained with the show throughout its run.

The actor then appeared in a string of made-for-TV movies through the 1990s and made two episodes of 'Curb Your Enthusiasm' in 2004 before starring alongside Drew Barrymore and Jimmy Fallon in the 2005 comedy 'Fever Pitch'.

His final on-screen appearance came in a 2012 episode of 'The Closer', where he played Judge Edward Crosby.