June 10, 2021 | 1:10pm

It’s “XXPEN$IVE” to have curves like hers.

Erika Jayne — who along with estranged husband Tom Girardi was recently sued for allegedly embezzling settlement funds intended for victims of the Lion Air Flight 610 crash — opened up about her costly and extensive skincare routine in a recent Glamour interview.

Among the more than $1,800 worth of products the 49-year-old “RHOBH” star uses to maintain her picture-perfect complexion? A “fierce ass” $305 Sisley-Paris cream designed specifically for use on the décolletage.

“Bust cream overall, in my opinion, is underrated,” Jayne said. “So many women think that skincare stops at their chin, and you’ve really got to take care of your neck and your whole décolleté because that shows age as well.”

Added the entertainer, “I don’t know why American women don’t use it more. European women love it. You wanna wear something low and plunging, you don’t need creepy, dried-out décolleté.”

Sisley-Paris Phytobuste   Décolleté Intensive Firming Bust Compound

Sisley-Paris Phytobuste Décolleté Intensive Firming Bust Compound ($305)

In addition to the “intensive firming bust compound” — which “smoothes the décolletage and immediately firms up breasts for a sensation of a smoother, more toned bust in a few minutes,” according to the product description — Jayne also slathers on Furtuna Skin Due Alberi Biphase Moisturizing Oil ($225), Sisley-Paris Black Rose Precious Facial Oil ($250) and Madonna’s MDNA Skin The Rose Mist ($90).

The “Housewife” is also a huge fan of celebrity-approved skincare line iS Clinical, relying on the Youth Intensive Creme ($225), Youth Complex ($154) and Youth Eye Complex ($105) to turn back the clock.

“Is it gonna give you an eye lift? No. A doctor does that. Botox does that. But does it moisturize those fine lines? Absolutely, and you need it,” Jayne told Glamour of the latter.

Famed lawyer Tom Girardi, from whom Jayne filed for divorce in November, soon after testified that he’s broke.

The former couple’s marital home is currently listed for $13 million as part of a bankruptcy sale, and Jayne — along with her many beauty products, presumably — downsized to a new $1.5 million house at the beginning of this year.