Owain Yeoman, Amanda Righetti

The Mentalist is officially saying goodbye to Wayne Rigsby and Grace Van Pelt.

Series regulars Owain Yeoman and Amanda Righetti will make their final appearances on Sunday's episode of the CBS drama, TVGuide.com has learned.

"It's a very exciting opportunity, I think, for fans to say their goodbyes to two beloved characters," Yeoman tells TVGuide.com about the episode. "It's a very dynamic episode. I think our show pushed the envelope. ... It felt very different than what we've done."

The Mentalist exclusive: What does Richard Haibach know about Van Pelt's kidnapping?

Adds Yeoman: "I'll be shedding a little tear on Sunday saying goodbye to my long-term buddy Wayne Rigsby."

But will Rigsby and Van Pelt's ending be a happy one? At the end of last week's episode, Van Pelt was kidnapped by an unknown person who's targeting former CBI agents. "The whole of the episode becomes this action-packed quest for Rigsby to quite literally save the life of his wife," Yeoman teases. "The stakes couldn't be higher for my character."

March Madness: The most memorable moments

Yeoman says the episode will show viewers a different side of Rigsby. "It's a very exciting episode for us," he says. "There's lots of twists and turns, and there's a bit of a badass side to Rigsby. Who knew?"

News of the their departures first surfaced in August, and Righetti confirmed the exits in November. The actress has since booked guest-starring gigs on Chicago Fire and its spin-off Chicago P.D., while Yeoman says he's exploring developing his own projects.

The Mentalist airs Sundays at 10/9c on CBS.

(Full disclosure: TVGuide.com is owned by CBS.)