Christie Brinkley vowed never to model in a swimsuit 30 years ago.

The 63-year-old model donned a revealing bathing suit to pose for the Sports Illustrated Swimsuit Issue in 1979 and promised herself that would be the ''last time'' she would be spotted in a skimpy beachwear garment, but the blonde beauty has since changed her ways and has returned to appear in the magazine wearing a black one piece.

When asked by PEOPLE about stripping off for her photoshoot, Christie said: ''My first thought was, 'At my age? No way!'.

''When I turned 30, I was like, 'This is the last time I'm posing in a bathing suit!' When this issue comes out, I'll be 63. I thought, 'Those days are over.'''

However, Christie's children Alexa, 31, and Sailor, 31 - who joined their mother on set to pose beside her - persuaded her to give modelling ''one last go''.

Christie explained: ''But to get to do it with my girls, I thought, 'One last go!'''

The 'Vegas Vacation' actress has taken to social media to showcase her enviously toned physique in the shoot, and to share how grateful she is to be asked to feature in the upcoming issue regardless of her age.

Alongside a picture of her and her daughters in their swimwear, which she shared on her Instagram account, Christie - who also has 21-year-old son Jack - wrote: ''Yes! I am excited to announce that I am back in @si_swimsuit ..I figured with my gorgeous daughters @alexarayjoel and @sailorbrinkleycook by my side whose going to be looking at me! Oh and My kids think I walk on water, so let's not mention the apple box concealed just under the surface. For a preview check out ..and thank you Sports Illustrated for sending the powerful message that good things come in packages of every size and we do not come with an expiration date! psI can't wait to see everyone at VIBES on Feb 17th and 18th in Houston! #proudmomhere! (sic).''