Mark Hamill and his wife Marilou York's marriage secret is acceptance.
The dental hygienist - who tied the knot with the Star Wars actor in 1978 - also says not worrying about things that are not important is also vital for a strong relationship.
Marilou told People: "Don't sweat the little stuff.
"And also, go in knowing you're not going to change anyone. So you have to accept their quirks and their behaviour."
Interrupting, Mark said: "What quirks?”
Agreeing, he said "acceptance" and "communication" are two vital components to a happy and long marriage.
The couple - who have sons Nathan, 46, and Griffin, 42, as well as 33-year-old daughter Chelsea - met in the mid-1970s at a dentist's office, where he was a patient and she was a dental hygienist.
And the pair have been smitten with each other ever since.
Mark said: “I just think that when you find the right one, the odds are against you.
"But if you do get lucky, you just have to hang on and be grateful that you were able to find that one."
Mark and Marilou have executive-produced a new documentary called Big Rock Burning, in which they look back on their community of 47 years - the Big Rock neighbourhood in Malibu.
In January, Mark, Marilou, and their dog Trixie were forced to flee their home - where they got married and their children were raised - and stay with their daughter Chelsea in Hollywood due to the Los Angeles wildfires.
However, Mark and Marilou's home "amazingly" survived the wildfires, and they are beyond grateful.
She said: "We got married there, we raised our kids there. It's a very, very special property.
“I'm so thankful and grateful that our house survived, but I just didn't realise the ramifications of it.”
Currently, the couple cannot return to their house because Mark said it is “toxic with chemicals".
