It's not easy being beautiful.

Kate Upton has landed on the cover of Sports Illustrated's swimsuit issue for the second year in a row, but she and the magazine's other models do not get along, according to Us Weekly.

"The SI models hate her," says a source about 20-year-old Kate. "They are jealous, but Kate's also been a bitch to them in the past."

Case in point: Things are so frosty between Kate and the other models that Kate completely ignored them during a party in Vegas last week.

"She didn't interact with anyone," according to an onlooker. "She wasn't friendly."  

And here we thought life would be carefree for people who get to lounge around in swimwear for a living. 

Source: Us Weekly