Errico plays a lawyer in the upcoming episode, which will air toward the end of January 2013.

The acclaimed singing actress told Playbill.com, "I'm obsessed with the 'Good Wife,' and was so thrilled to get to audition. I had to play a very argumentative lawyer, Ingrid Ballantine, who, in court, objects often! At the audition, the director, Rosemary, asked me to do the first scene again and make sure that I talked over Alicia's [Julianna Margulies'] lines, barging in on her and getting the judge to shut me up. That was fun! Also, the legal details — which I cannot divulge in case it tips something off — were a little tricky, and I realized during the audition that I was saying a few things I didn't really understand…or I wanted to make sure I did.

"As I was leaving the audition," Errico added, "I was still talking to myself, thinking it through – as I walked out the door! The director told me she cast me because of the way I walked out the door. She said she could tell I was really in it and really was going to grapple with it, and enjoy it, which I did. I had the most fantastic time! Kyle MacLachlan and I talked a lot, and he tweeted a photo of us from the set. I had English black tea — no milk — and nuts with Alan Cumming during our breaks. I'd met the incredible Julianna before at a playground with our children, and it was a thrill to work with her. Nicest people in the most awesome show, hands down."

Melissa Errico, most recently seen on Broadway in Irving Berlin's White Christmas, began her professional career portraying Cosette in Les Misérables, and she followed with leading Broadway roles in Anna Karenina, My Fair Lady, High Society, Amour (Tony nomination) and Dracula, plus roles in the City Center Encores! productions of Call Me Madam and One Touch of Venus. She appeared in a production of Threepenny Opera at the Williamstown Theatre Festival, and her recent Off-Broadway credits include Candida (Drama Desk nomination for Outstanding Actress in a Play), Finian's Rainbow and Aunt Dan and Lemon. She also starred in the Hollywood Bowl presentations of Camelot and The Sound of Music.

Her newest solo recording, "Legrand Affair," produced by Phil Ramone and featuring a 100-piece symphony arranged and conducted by Legrand, is available from Ghostlight Records. Read more about Melissa Errico in the Playbill Vault.

"The Good Wife" airs Sundays at 9 PM ET on CBS; check local listings.