Catherine Zeta-Jones called her father-in-law Kirk Douglas a “hero” as she marked his 101st birthday.

The actress celebrated the landmark birthday of her husband Michael Douglas’s father with a sweet tribute on Instagram.

Zeta-Jones wrote: “101 today!!!! My darling Pappy on my knee.

“Happy Birthday to my wonderful, inspirational and loving father in law, Kirk. Love you with all my heart. #hero”

Screen icon Douglas was born on December 9, 1916.

Across a career that has spanned seven decades and includes three Oscar nominations, as well as an honorary Academy Award in 1996, Douglas is best known for roles in Spartacus (1960) and 20,000 Leagues Under The Sea (1954).

He has also starred in a number of Westerns, including Along The Great Divide (1951) and Lonely Are The Brave (1962), as well as early Stanley Kubrick film Paths Of Glory in 1957.

The most recent film he appeared in was 2004’s Illusion, about an ailing movie director, and in 2008 he featured in TV movie Empire State Building Murders.

His Hollywood star son Michael, 73, last year said that he was wishing his father to reach the grand old age of 101.

Douglas has been married to Anne Buydens, his second wife, for 63 years and has seven grandchildren – Cameron Douglas from Michael’s marriage to Diandra Luker, Carys Zeta Douglas and Dylan Michael Douglas from Michael’s marriage to Zeta-Jones, and Tyler, Kelsey, Ryan and Jason Douglas by his son Peter.