Toby Keith, Brad Paisley, Martina McBride and ... Rihanna?

The R&B superstar is the most surprising name on the guest list for the Academy of Country Music Awards on April 3, where she'll perform her song 'California King Bed' with Sugarland's Jennifer Nettles, according to RyanSeacrest.com.

While a number of unexpected pop artists have shown up at country music award shows in recent years, Rihanna may be the biggest surprise, given recent performances like her steamy Grammy duet with Drake or her controversial Brit Awards rendition of 'S&M.'

But 'California King Bed' should fit in better with the ACM crowd. It's a ballad taken from Rihanna's latest album 'Loud,' which has already achieved platinum status.

Could this be a ploy on the part of the ACMs to attract more viewers? Perhaps, but we'll definitely be watching.

Among the other scheduled ACM performers familiar to pop fans are crossover star Taylor Swift, 'American Idol' alum Carrie Underwood, and Rock and Roll Hall of Famer James Taylor, who will sing with the Zac Brown Band.