Ad by Chinese lingerie firm Jealousy International feauturing a Princess Diana lookalike and the slogan: "Feel the romance of British royalty, Diana underwear." Photo: Tim Stewart News/ Rex USA

We've seen some tacky lingerie in our time, but this really takes the cake.

A Chinese lingerie brand inspired by Princess Diana is featuring the late royal -- on the 13th anniversary of her death, no less -- in bra and panties as part of its new campaign, the Daily Mail reports.

Yesterday Jealousy International unveiled a new billboard for its Diana underwear range, urging shoppers to "Feel the Romance of British Royalty" and depicting a lingerie- and tiara-clad Diana look-alike playing a cello for a small child, according to the paper.

Um, yeah.

While a representative for Prince Charles had no comment, a British traveler told the Daily Mail his reaction to the shocking ad.

"I was just going to collect my baggage from the carousel when I saw it flash up on a rolling advertising screen and couldn't quite believe what I was seeing," Sam Chambers said of the airport billboard.

"I thought, surely not, because it was rolling quite quickly. So I waited to check when it came up again and, sure enough, there was an image of Diana."

Disturbing! Then again, it's not the first time a royal's underwear has gotten some attention -- Queen Victoria's knickers raised eyebrows when they were declared a "national treasure" last year.

In other royal news, Princess Beatrice has ranked high on the World's Hottest Bikini Bodies List.