Taylor Swift probably wants to know why Jay-Z has gotta be so mean.

The rapper appears to slam T-Swift in his new song from the Great Gatsby soundtrack, according to Hollywood Life.

In the tune, called "100$ Bill," Jay-Z raps about having lots of money.

“Took that, Taylor Swift to a hundred f**king million, bitch,” he raps.

So what exactly is this referring to?

It appears to be a reference to Kanye West's run-in with Taylor at the 2009 MTV Music Awards.

Jay-Z seems to be saying that Kanye is famous because of the notorious incident and doesn't feel remorse for embarrassing Taylor.

Indeed, Forbes estimates Kanye's net worth at $100 million. Jay-Z's net worth has been estimated at around $500 million.

It's hard to know what exactly Jay-Z has against Taylor, or why exactly he chose to call her out. And is he saying that Taylor is a "bitch"? Harsh!

We're wondering if Taylor will respond as angrily to this diss as she did to Amy Poehler and Tina Fey's jokes about her at the Golden Globes.

Taylor has been known for writing songs about real-life people whom she has issues with, and now it seems that she's getting a taste of her own medicine.

Source: Hollywood LifeCelebrity Net Worth