Goldie Hawn shares secret to 40-year relationship with Kurt Russell

Goldie Hawn has shared the secret behind her 40-year relationship with Kurt Russell.

The 78-year-old Hollywood star has dated 73-year-old Russell since Valentine's Day 1983 and they share son Wyatt Russell, 38 - but have never married.

Speaking to E! News on Friday, Hawn was very clear about the secret behind her long-lasting relationship, saying, "You have to have good sex. Because sex is something that connects you and creates more belonging... people who have healthy sexual relationships usually last a lot longer."

The Overboard star went on to explain that couples who hope to stay together for decades need to focus on other areas too.

She said, "But it's not just because of the act, it's because of the warmth and the intimacy that it creates."

And she added, "You have to be nice to each other upon occasion."

Shining further light on her romance with Tango & Cash star Russell, Hawn admitted they don't always agree.

She said, "You know you're not the same person. You don't think the same way oftentimes. And you have to accept that, but you have to measure are we having fun, or is this something we want to do? Do we have laughs together? Do we share certain things? You don't have to share everything."

She also urged other couples not to compare themselves to others, warning, "We have a lot of expectation, I think, around relationships, but you have to like the person. That's very important."