Cindy Crawford thinks tequila is the secret to a happy marriage.

The 49-year-old supermodel has been married to Rande Gerber since 1998 and believes their success is down to the strong spirit.

She joked: ''I definitely think [tequila is the secret to a happy marriage]. I mean, we met on tequila!''

And Cindy is thrilled her husband was able to create his own tequila brand, Casamigos, with the pair's close pal George Clooney.

She added to Us Weekly magazine: ''It's so fun because Rande is such a bar guy and a nightlife guy, and then for him to finally kind of culminate his career with doing a tequila that we really just did for ourselves and friends, and then turn it into a business.''

Meanwhile, Rande previously joked they were ''forced'' into starting a tequila business because they were ordering so many bottles.

He shared: ''George and I started drinking tequila a very long time ago. There came a point when George said to me, 'Why don't we just make our own.' We never meant it to be a business.

''We started out just us drinking it, without anyone being able to buy a bottle. We were kind of forced into [making it a business], after about two years, we got a call from our distillery and they said to us, 'We have a situation. For the past two years, we've sent you a thousand bottles a year. Either you're selling it, or you're drinking way too much. You need to get licensed and get legit with the situation.''