Sylvester Stallone and William Shatner have led tributes to Brian Dennehy.

The Hollywood actor died of natural causes aged 81 on Wednesday (15.04.20), and Stallone - who starred alongside him in Rambo movie 'First Blood' - praised the late star as a ''brilliant performer'' and said he helped him build the character of John Rambo in the motion picture.

He wrote on Instagram: ''The great actor Brian Dennehy has passed away. He simply was A brilliant performer ... He also was a Vietnam vet that helped me very much building the character of RAMBO The world has lost a great artist. #First Blood (sic)''

William Shatner tweeted: ''Condolences to the family of Brian Dennehy. A wonderfully talented actor.''

Russell Crowe - who starred alongside Brian in 2010 thriller 'The Next Three Days' - remembered the late star as a ''fine actor'' and ''good company''.

He tweeted: ''Brian Dennehy has passed.

''He was a fine actor .

''He was good company.

''(golden globe, 6 Emmy noms, 2 Tony wins & an Olivier award)

''Watch - The Next Three Days (2010) Directed by Paul Haggis. Underrated movie.

''It was a privilege to work with him. Condolences to his loved ones. (sic)''

'A Clockwork Orange' actor Malcolm McDowell shared: ''Very sad to hear about the passing of Brian Dennehy. He was a fantastic actor on the big and small screens, as well as theatre. Another great loss!!! RIP MM (sic)''

Mia Farrow admitted there were ''few friends as valued in [her] life'' as Brian was.

She wrote on Twitter: ''Just devastated to learn that the magnificent Brian Dennehy has died. They is no one i enjoyed working with more. And there are few friends as valued in my life. (sic)''

Brian's daughter Elizabeth Dennehy confirmed he passed away from natural causes, and said he will be missed by many.

She tweeted: ''It is with heavy hearts we announce that our father, Brian passed away last night from natural causes, not Covid-related. Larger than life, generous to a fault, a proud and devoted father and grandfather, he will be missed by his wife Jennifer, family and many friends. (sic)''

Brian began his lengthy career in the 1970s with guest roles in TV shows including 'Kojak', 'M*A*S*H', and 'Lou Grant'.

He appeared in one episode of 'Dallas' in 1978, where he played Luther Frick, and in five episodes of 'Dynasty' in 1981 as D.A. Jake Dunham.

The late star had his breakthrough film role in 1982 when he starred as Sheriff Will Teasle in 'First Blood', and he played the leading man in 1987 thriller 'Best Seller', which co-starred James Woods.

He was also known for his role in the 1995 Chris Farley-David Spade comedy 'Tommy Boy' as Big Tom Callahan.

Most recently, Brian starred as Mr. Cilliano in 2018's 'Tag', and had a role in the upcoming movie 'Son of the South', which is currently in post-production and will be a posthumous role for the star.