This Thursday's episode of Grey's Anatomy, "Holidaze," combines Thanksgiving, Christmas and New Year's - and notably features the arrival of Mark Sloan's long-lost ... daughter.

Yes, a hot, blonde, McSteamy spawn. We'll pause for a moment to let that sink in.

Aside from guest star Leven Rambin (who plays the character from Mark's past, whomever she is), Thatcher Grey and Miranda's as-yet-unseen father also appear in the episode.

Click to enlarge some photos from "Holidaze" below and see what you think ...

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