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"House"-hold name: Sasha Pieterse as Andie.
"House"-lights: Andie is a 9-year-old girl with terminal cancer who is hallucinating. But the cancer is in remission and it turns out the hallucinations are caused by a blood clot. The team puts her into a chemically dead state and performs an "autopsy" in order to find the clot. In the end, her bravery inspires House to go buy his motorcycle. Also -- Andie uses her terminal illness to get Chase to kiss her, which horrifies Cameron.
Out-"House": Sasha Pieterse may not have been famous when she was on "House," but she is now playing the trouble-causing Alison on "Pretty Little Liars."