Be warned, Kanye West: Taylor Swift has written a song about you, and she’s singing it at Sunday’s MTV Video Music Awards.

But that’s just one of the twists that are sure to keep viewers glued to their seats for this year’s awards.

Paramore, Bruno Mars and B.O.B. had some fun on stage as they rehearsed the three-song medley they’ll perform on Sunday’s show.

During Saturday’s rehearsal, Mars crooned “beautiful squirrels” instead of “beautiful girls” as he and rapper B.o.B. prepared to run through their hit, “Nothin’ on You.”

Later, Mars entertained himself and a few dozen workers inside the Nokia Theatre by singing the 1978 Police hit “So Lonely.”

“Why are you trying to sing higher than me?” Paramore lead singer Hayley Williams asked playfully over the microphone.

“Sorry,” Mars sheepishly responded.

Not to be outdone, B.o.B. chimed in with a few verses from Cee Lo’s expletive-laden new single. Mars accompanied him on piano.

Mars and B.o.B. also beat-boxed between performances of their medley, which also includes the rapper’s “Airplanes” and the rockers’ “The Only Exception.”

Williams confessed that she got a little turned around on the show’s expansive, space-age set with its sloping canopies and multiple video screens.

“I thought the stage was over there,” she said, running to her spot in front of the band. “I was lost, but now I’m found.”

The three young entertainers are among a slate of performers expected at Sunday’s ceremony, including Kanye West, Eminem, Usher and Mary J. Blige.

Meanwhile, Swift wrote a song about her win for best female video last year when Kanye West got on stage and said it should have gone to Beyonce.

A source familiar with the show said Saturday the 20-year-old will sing the new song at the VMAs, which will be aired live on MTV. The source did not want to be identified because of the sensitivity of the matter.

The song is on Swift’s upcoming album Speak Now, due out in October. The source said Swift performed it during a secret rehearsal in Los Angeles for the VMAs on Friday.

Though the West-Swift moment only lasted but a few minutes, it has endured for what seems to be a lifetime.

It became a cultural watershed moment and gave West the most intense backlash of his career, despite an apology.

He dropped out of the spotlight, and last week on Twitter, said that he endured death wishes, had to cancel a tour and let go of employees.

He again apologized to Swift and said he wrote a song for her and hoped she would sing it — and if not, he would perform it for her.

Though there was anticipation of possible fireworks related to last year with West’s performance, Swift’s song all but guarantees it.

Copyright 2010 The Associated Press.