People are reselling Sydney Sweeney's used bathwater for insane amount after it sells out immediately

Sydney Sweeney isn't letting a lucrative business venture go down the drain.

The craze for soap made from the actor's used bathwater is showing no signs of slowing down, as people are now reselling the products for astronomical amounts online.

For anyone who's confused by what I'm talking about, Euphoria star Sweeney decided to recycle her bathwater post soak and create her very own soap line with skincare brand Dr Squatch – because, why not.

The bold idea follows a previous collaboration between Sweeney and the men's skincare line, which saw the 27-year-old actor star as a 'body wash genie' in commercials for the brand last year.

Following the popularity of having the actor's name attached to the brand, Dr Squatch partnered up with Sweeney once again and created the aforementioned 'Sydney's Bathwater Bliss.'

A move which has been very popular with certain fans of the Anyone but You star.

Sydney Sweeney isn't letting a business venture go down the drain (Jon Kopaloff/Getty Images for Lionsgate)

"When your fans start asking for your bathwater, you can either ignore it, or turn it into a bar of Dr Squatch soap," Sweeney said of the venture in a press release.

Priced at a reasonable $8 (£5.90) and coming with a certificate to guarantee the inclusion of water which Sweeney had bathed in - which seems a little counter-productive for a product used for cleaning yourself - went on sale last week (6 June) and sold out within seconds.

Several fans were left empty handed during the online frenzy to snap up the bars, with Dr Squatch revealing on social media accounts that increased demand had crashed their website.

However, anyone who's disappointed at not being able to wash their hands in the same water which Sweeney has touched shouldn't feel too sad, as you can still snap up the soap via the secondhand market.

For an increasingly inflated price.

A quick search for the soap on eBay reveals the bars are now retailing around the £200 mark, with some selling for as much as $2000 (£1478).

The bar of soap has proven to be hugely popular (Dr Squatch)

Meanwhile, a seller is currently selling one quarter of the bar for £105 and another has a listing for a picture of the soap for just under £73.

Which means some people are looking make rather nice return on their initial eight dollar investment.

Sweeney has since revealed the bold venture was her very own idea, opening up to E! News about the venture at the premiere of her Apple TV+ film Echo Valley.

"I think it’s more fun to see everyone else talk about it," she told the outlet. "I pitched it."

We certainly can't fault Sweeney's entrepreneurial spirit.