The iconic model, who shot to fame in the 1970s after marrying photographer David Bailey, joins the increasing list of older women from Joni Mitchell to Joan Didion who prove that style has no age limit.
The range is designed by Aliza Reger, which makes it something of a homecoming for Helvin, who is thrilled to be part of the campaign.
"Janet Reger was such an iconic brand throughout my modelling career," she says, "and it feels great to now be modelling her daughter’s range for JD Williams almost forty years on."
The launch comes after feedback from customers showing women over 50 felt the high street did not offer fashion forward lingerie to suit their physiques.
The fashion retailer ran a study into body confidence levels in older women, which revealed lingerie to be the least popular clothing item in women's wardrobes.
So, the range has been designed specifically to flatter the over 50s figure with palettes including floral prints, pastels and lace panels.
Talking about her work process, Aliza Reger said: "I took inspiration from heritage pieces."
The new Always Aliza collection launches 1 July in bra sizes B- F and briefs in 12-32 at JDWilliams.co.uk, prices start from £14.