Evan Agostini / Invision/AP 1 / 7
Evan Agostini / Invision/AP 1 / 7

"Has she, or hasn't she? That is the big question. And here is the answer: only your dermatologist should know for sure."

That's how Christie Brinkley kicks off a long and detailed piece about plastic surgery and other forms of physical tweaking -- including information about how to find the right doctor -- published over the weekend in the Daily Mail.

The seemingly ageless 61-year-old, who's still nothing short of stunning in a bathing suit, recently released a book about looking good, based on her own experience with various beauty regimens. In her feature for the Mail, she shares some of the highlights from "Timeless Beauty: Over 100 Tips, Secrets, And Shortcuts To Looking Great," from Botox to non-surgical fillers to physiotherapy.

For starters, Christie admits that while she uses Botox, she's not a fan of using it to relax facial muscles.

"Botox took the arch out of my eyebrows and made me look sad," she writes, adding that she never used the stuff in her face again.

That said, she has found Botox to be successful in remedying the effects of age in her neck, where she noticed "vertical bands" had started to appear over time.

"It worked wonders to relax those muscles and it also tightened my double chin area and jawline. The best part is that you don't have to worry about any expression being lost or changed," she writes.

Warning to readers to "fill, don't stuff," Christie also shares her thoughts on the best practices for fillers.

"I've used them on an indentation on my forehead - the legacy of a playground accident - and also on marionette lines around my mouth," she writes. "But you must use a very small amount because over-filling removes contours and gives you a flat face."

Another procedure the veteran model has had good luck trying is the Clear + Brilliant laser, which she used on her face to treat discoloration. "The process also stimulates your body to produce collagen, the naturally occurring protein in the skin that gives it firmness and elasticity, so I get the added bonus over time of my face looking fuller and more youthful," she notes.

The non-surgical lifter Tripollar, meanwhile, has helped Christie battle lines above her knees.

As for the internal effects of aging, Christie suggests that surgeries such as hip replacements aren't always necessary, and details the various accidents she's had through the years that she's treated with a process called physiotherapy instead.

"The best results," she concludes, "are not total transformations but nearly imperceptible changes that just make you look like a slightly younger version of you."

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Christie Brinkley posts makeup-free selfie