The milestone episode is to air later this season on the network.
"Our 200th episode is going to be a special show," executive producer and show-runner Erica Messer said in a statement. "We can't imagine telling this story without Paget being present."
Brewster played Emily on the show for six seasons with her last episode airing May 16, 2012.
The series co-stars Joe Mantegna, Thomas Gibson, Shemar Moore, Matthew Gray Gubler, Kirsten Vangsness and Jeanne Tripplehorn.
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