Maura Tierney has revealed that she has found a tumor in her breast, following weekend reports that the illness has pushed back the premiere of her new NBC fall drama Parenthood.

"In an effort to guard my privacy, it seems that the wording of NBC's press release has unfortunately caused some confusion and undue alarm about my health. I have discovered a tumor in my breast which requires surgery," Tierney, 44, tells Usmagazine.com in a statement.

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"I will not know either my exact diagnosis or course of treatment until that surgery is performed. My doctors have all assured me this is a very treatable condition," she goes on. Adds the actress, "I'm very optimistic as to the outcome and want to thank everyone who has sent positive thoughts and support. I look forward to going back to work soon."

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Parenthood, a contemporary reimagining of the 1989 comedy, had been scheduled to begin filming July 27. No air date has been set. Tierney is best known for her 10-year stint as Dr. Abby Lockhart on NBC's ER, for which she earned an Emmy nomination.

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