Credit: Instagram

Who has the darker tan?

Kim Kardashian challenged Patricia Krentcil, the New Jersey woman now known as "Tanning Mom," on Twitter Saturday.

Kardashian, 31, tweeted a photo of herself and wrote, "The tannerexic mom has some serious competition!!! Lol." In the Instagram photo, the reality star shows off her shockingly dark face and chest after getting a spray tan.

But don't worry, it's not permanent.

"Relax that's just a spray tan!" she tweeted. "It washed off & I'm back to my normal tan self! But how crazy does it look after being on for 8 hours!"

"How do you spell tanorexic anyway?" she added. "Tannerexic? Tannorexic? Is this even a real word?" 

Krentcil, 44, made headlines earlier this month when she pleaded not guilty to second-degree child endangerment after being charged with allowing her 5-year-old daughter to tan in a tanning booth.

Some experts claimed the mother, who admitted to excessively tanning herself, suffers from "tanorexia." Krentcil said in court, "I'm very tan and I've been tanning my whole life."