Joanna and Dean forever.

Goldie Hawn has a simple secret to why her four-decade relationship with Kurt Russell continues to be a success – “good sex.”

“Because sex is something that connects and creates more belonging. People who have healthy sexual relationships tend to last much longer. But it’s not just because of the performance, but also because of the warmth and intimacy it creates,” Hawn told E! News at their Love In Gala celebrating the Goldie Hawn Foundation and MindUP’s 20th anniversary on September 27th in LA.

She also joked, “You have to be nice to each other every now and then.”

The couple has been together since 1983. They first met on the set of The One and Only, Genuine, Original Family Band in 1968, but it would be years before they became officially romantic.

They starred in 1984’s “Swing Shift” before reuniting on screen in the 1987 Garry Marshall-directed comedy “Overboard.”

“You know you’re not the same person,” the Now and Then star explained over the weekend. “You don’t often think in the same way. And you have to accept that, but you also have to measure: Are we having fun or is this something we want to do? Do we laugh together? Do we share certain things? You don’t have to share everything.”

The First Wives star continued, “I think we have high expectations for relationships, but you have to like the person. “That’s very important.”

Hawn, 78, and Russell, 73, never married but are parents to actor son Wyatt Russell, 38. Kurt also welcomed son Boston Russell with his ex-wife Season Hubley and Hawn is the mother of actors Oliver and Kate Hudson, who they had with the musician Bill Hudson.

Kurt also spoke about their relationship when they attended the event on Friday.

“I think most people who have been together for a long time have one thing in common,” the “Christmas Chronicles” actor told E! News. “And that means that after so many years together, you have experienced pretty much everything you can experience together and understand all the ups and downs and what they mean.”

“I just love the fact that we met and still do. We still enjoy being together.”

The couple has been vocal over the years about not tying the knot. But they’ve often gushed about how they met.

“I was 21 and he was 16 and I thought he was charming but he was way too young,” the actress told Desert Island Discs on BBC Radio 4. “And years later we met again and I liked him and remembered him I liked him a lot when I first met him. But we both said we would never date another actor, which just goes to show you can never really tell.”

Their first date ended with a night of dancing at the Playboy Club in Manhattan – but they concluded that “the night wasn’t over yet.”

“Eventually we found our way upstairs, looking around at imaginary furniture, and now we’re in the imaginary bedroom, and we’re actually having sex,” Kurt recalled of an appearance on “Harry” in 2017, “when the police came in because . “We had to break in there to get in.”

“That was our first date,” he continued. “It was a lot of fun, I’ll tell you what. I can’t believe it’s been a long time.”