"Grey's Anatomy" Season 10, Episode 21, titled "Change of Heart," airs on ABC on Thursday, Apr. 24. This week's new episode is dubbed "Farewell to Cristina" in a promo video. Ellen Pompeo, who plays Cristina's "person," has bid Sandra Oh goodbye on Instagram. Meanwhile, Preston Burke (Isaiah Washington) returns to Grey Sloan Memorial in Episode 22.

Spoiler alert: This feature contains spoilers and speculations on Grey's Anatomy Season 10. Episode 21 ("Change of Heart") is believed to be Yang-centric. Read at your own risk.

There are 24 episodes in Grey's Anatomy Season 10. Episode 21 is promoted as "Farewell to Cristina" but it is believed there is a long goodbye for Yang in this Shonda Rhimes creation. It has been months since Rhimes and Oh confirmed Yang's exit in the season finale. This "goodbye" is going to be elaborate.

Jackson Avery (Jesse Williams) is delivering some bad news in Grey's Anatomy Season 10, Episode 21. But it is probably not about Yang. Cristina is mentioned in the synopsis for Episode 22, where Burke returns. Fans have been endlessly speculating on what happens next. Isaiah Washington has some teasers.

"It's gonna blow your mind. You are not ready. You can't figure it out. You can't figure out, Shonda [Rhimes]. I don't know what she eats," Washington tells BuddyTV.com. Follow this link for BuddyTV's full length interview.

Preston Burke was last seen on Grey's Anatomy in the Season 3 finale, "Didn't We Almost Have It All?" This heart-crushing episode - where Yang asks Mer to tear open the wedding gown she's wearing -- aired seven years ago.

Meanwhile, Ellen Pompeo recently posted on Instagram a photo of her with Sandra Oh. The caption reads: "So proud of the work we've done together @iamsandraoh we've laughed we cried we've kicked some serious acting ass together #sograteful." To many Grey's fans, Meredith Grey is officially saying goodbye.

Shonda Rhimes is known for killing off her characters in a merciless-to-fans fashion. How will Cristina Yang exit Grey's Anatomy Season 10?

Caterina Scorsone ("Private Practice") guest stars in Grey's Anatomy Season 10, Episode 21 as Derek's sister Amelia. Debbie Allen ("Fame") also returns as Catherine Avery. Watch the "Farewell to Cristina" promo clip here.

Wow, #GreysAnatomy production wraps tomorrow. Ten seasons. Mind blowing for me that something I thought up in pjs has lasted so long...

— shonda rhimes (@shondarhimes) April 24, 2014

WATCH: Grey's Anatomy Season 10, Episode 21 ('Change of Heart') | ABC on YouTube | Promo Video

In this Grey's 10x21 sneak preview below, Cristina Yang tells the parents of three sick children that they have to choose the child who gets a heart transplant. This happens after Yang loses a Harper Avery award. (Watch the same clip on this YouTube page.)

Grey's Anatomy Season 10 airs Thursdays on ABC. The last major and "beloved" characters to die on this Shonda Rhimes drama are Lexie Grey (Chyler Leigh) and Mark Sloan (Eric Dane). Adele Webber (Loretta Devine) and Heather Brooks (Tina Marjorino) have also passed on since. But grieving took much longer for Little Grey and McSteamy fans. If Cristina Yang dies, some fans are saying on Twitter they will stop watching Grey's Anatomy.

More TV Guide and Spoiler Features

'Grey's Anatomy' Season 10 Spoilers: Shonda Rhimes Prepares Fans for the Big Cristina Yang Goodbye [Watch 10x19 Promo Video]
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