Malcolm McDowell says respect is the secret to his 34-year marriage

The A Clockwork Orange star told People: "You know what? Honestly, I am not an expert on relationships. I wish I was.

"And I think just liking the partner you're with is very important and just respecting."

Kelley - who has sons Beckett, 21, Finnian, 18, and Seamus, 16, with Malcolm - is a visual artist, and he is in awe of her talent.

Malcolm gushed: "My wife's a brilliant designer and at the moment, she's doing this house in Mexico, which is her masterpiece.

"It's an amazing thing that she's done, and I'm so proud of her."

Despite Kelley and Malcolm - who live in Ojai, California - having two different careers, they do put aside some time to enjoy their shared interests, such as visiting antique shops because they are avid collectors.

The Son of a Critch star said: "She doesn't do what I do, but she's just as successful in her own way, and I'm in awe of what she does.

"It's amazing. I don't know how she does it, but she does it, but we also, we're collectors.

"We collect stuff, and we pretty much collect and like the same stuff, which is lucky.

"That, and it's a lot of fun."

Malcolm is also a dad to daughter Lilly, 44, and son Charlie, 42, with his ex-wife, 72-year-old actress Mary Steenburgen, and a grandfather to four girls.

In January, Charlie and his wife, Emily in Paris actress Lily Collins, 36, announced they had welcomed a daughter named Tove via a surrogate.

Malcolm says she is "absolutely gorgeous".

He added: "[Tove is] absolutely beautiful."

And speaking about his four grandchildren, the Halloween actor said: "I love being around them and just watching the antics that go on and the dynamic and the difference between them all. It's staggering.

"They're so different in personality and everything. It's just beautiful to watch."