Greys Anatomy
Reuters

Tons of interesting things are going to happen on Grey's Anatomy before it ends Season 13. And one of the most anticipated events is Maggie finally finding out about Meredith and Nathan's relationship.

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Meredith hooked up with Nathan before she knew her half-sister was interested in the surgeon. But Meredith has been a good sister since then, doing her best to stay away from Martin Henderson's character. But this is all going to change in one of the upcoming episodes when Meredith, the role played by Ellen Pompeo, and Nathan will be forced to confront their feelings when stuck together in an airplane.

So, how will Maggie react when she finds out about Meredith and Nathan? Maggie portrayer Kelly McCreary told TVLine that the truth will be out before the end of the season and that it may not affect Maggie the way people expect.

"People will have to be honest, because they no longer have a choice. It doesn't hurt Maggie in the way that the audience will expect it to," McCreary said. "In a relationship that you're committed to because you love each other unconditionally, the way that family does, challenges can sometimes make you stronger."

Ellen Pompeo
Pictured: Actress Ellen Pompeo, from the ABC drama series "Grey's Anatomy," arrives at the 2015 People's Choice Awards in Los Angeles, California January 7, 2015.Reuters

Meanwhile, this Thursday's episode is titled Till I Hear It From You and it will once again focus on Amelia as her mother returns to the hospital for treatment.

The official synopsis for Season 13 episode 17, which will air on March 23 at 8 pm ET on ABC, reads: "Maggie's mom returns to the hospital, but Maggie's still in the dark about why she's really there. Meanwhile, Owen and Amelia hash out their problems as they work on a trauma case together; and Bailey tries to mend her relationship with Richard."