Laura Dern described her mother as “my endless inspiration” as she wished her happy birthday.

The Hollywood actress said her mother, actress Diane Ladd, was “the best darn actor ever” as well as “my favourite buddy to go for a swim with”.

It comes just one day after she celebrated her own daughter’s 18th birthday in a separate heartfelt Instagram post.

Sharing a picture of her and Ladd in matching red dresses, she wrote: “Happy birthday, goddess mama!

“You are my endless inspiration and my favorite buddy to go for a swim with!! And just the best darn actor EVER.”

Dern is the daughter of Ladd and fellow actor Bruce Dern, though the pair separated in 1969.

The trio received adjoining stars on the Hollywood Walk of Fame on November 1 2010.

In a post on Monday Dern said her daughter teaches her how to be “an honest and profound empath”.

Sharing a selection of photos she wrote: “My baby is 18 today!!!

“Happiest birthday, Jaya! You teach me every day about what it means to be an honest and profound empath, artist, and activist.

“I love you with everything.”

Dern shares Jaya and her son Ellery Walker with her ex-partner Ben Harper.

The couple were married from 2005 to 2013.