Christie Brinkley's daughter has given her the confidence to wear a swimsuit.

The 70-year-old model features in the 60th anniversary issue of Sports Illustrated Swimsuit, and Christie has admitted that Sailor, a 25-year-old model, has helped her mom to feel confident about her body.

Christie - who appears on the cover alongside the likes of Martha Stewart, Tyra Banks and Winnie Harlow - told PEOPLE: "Sailor is very strong and, you know, she has very strong opinions about feeling good about yourself because she's gone through strong feelings, not feeling good about herself.

"So, she's really into empowering herself to feel confident and good. And she'll say to me if ever I, I'm doubtful and I go, 'I don't know, you know, is this like...?' She's like, 'Mom, you're beautiful, embrace it, you know, go with it, lean into it.' And I'm like, 'Ok, I shall try.'"

Meanwhile, Christie took to social media earlier this week to express her pride over the magazine cover.

The model also confessed to being surprised by her own longevity in the industry.

Alongside a photo of the magazine cover, she wrote on Instagram: "I feel so lucky to have gotten to know some of these fabulous individuals pictured here…amazing women who inspire and excel!

"I am grateful beyond measure for my many happy adventures with @si_swimsuit

"If someone came up to young permed sunburned me during my first photo shoot with the iconic magazine and whispered “they will still be inviting you to be in the picture at 70”, I would have laughed at them and called them crazy. But now I know that no one wants to become invisible because of our age, (or ethnicity, size, gender, or anything for that matter!) So thank you S.I. … you may just be 60, but you’re very smart for your age! (sic)"