Taylor Swift will likely avoid Carrie Underwood at the Grammys as if her rival's last name was Mayer.

Or Gyllenhaal ... or Kennedy ... or Lautner ... or Jonas ... or Styles ... or ...

You get the idea.

A source told Us Weekly the singers are bitter enemies who plan to avoid each other at Sunday's Grammy Awards. According to the insider, Grammy execs were ordered to keep Swift, 23, and Underwood, 29, "from crossing paths" at the Feb. 10 show "since they hate each other."

Actually, it would be a much better show if they did just the opposite.

A friend of Swift's told the Us, "Taylor feels Carrie is always rude to her, so she steers clear of her."

A Grammy rep said "No requests were received from either artist."

The feud could have intensified at the Country Music Association Awards in November, when co-hosts Underwood and Brad Paisley mocked Swift's relationship with Conor Kennedy.

"The greatest trade of the year had to be the Kennedy family. They somehow traded Arnold Schwarzenegger for Taylor Swift," Paisley said about Swift dating the 65-year-old bodybuilder's nephew through marriage. "I mean, what they got for that . . ."

Underwood interrupted him, pointing out that the pair had just broken up.

"What? Why don't I ever hear about these things? I'm the last one to know," Paisley said. "Are they ever gonna get back together?"

"Never, never, never," Underwood replied, referencing Swift's No. 1 hit single "We Are Never Ever Getting Back Together. "Never ever."

That's actually pretty funny.

Swift is set to open the Grammys show at L.A.'s Staples Center Sunday.

Contact Tony Hicks at thicks@bayareanewsgroup.com, on Facebook at www.facebook.com/BayAreaNewsGroup.TonyHicks, or on Twitter at twitter.com/insertfoot.