Earlier in the week, the 84-year-old Tony Award-winning playwright, who won the 1992 Pulitzer Prize for Lost in Yonkers, had informed the management of TACT/The Actors Company Theatre that he and his wife, Elaine Joyce, would be attending the jewel-box-sized staging at the Beckett Theatre.

"We kept it really top secret, we didn't tell the cast," TACT co-artistic director Jenn Thompson, who directed the production, told Playbill.com. "It would have made it too nervous-making to know that a titan, an icon was in the theatre."

Following the performance on Friday night, TACT general manager Cathy Bencivenga went backstage and told the cast to gather on stage — that Neil Simon wanted to meet them.

"You could hear them roar backstage," Thompson said. "It was like Christmas morning for them. It felt like delivering Santa Claus himself."

Simon came up onto the Beckett stage and "hung out in the Kurnitz living room with us," chatting with the cast and sitting on the couch in a parlor setting usually populated by characters — the dysfunctional Kurnitz family — who were based on members of Simon's family. He posed for pictures. "He was really warm and lovely and generous," Thompson said. "In addition to being complimentary about the production, which was great, he told me that Lost in Yonkers was his favorite thing that he's written."

This is the second TACT production of the season in which a living author was celebrated. Co-artistic director Scott Alan Evans directed A.R. Gurney's Children in fall 2011, and the playwright met with the director about the work. Gurney also participated in a post-show talkback.

"For me, I'm slightly embarrassed to admit, the ultimate experience that night was watching him watch the play," Thompson said of Simon's visit. "To see him laugh, and put his hand to his heart throughout the performance, was so gratifying."

She added, "You want that guy's stamp of approval. You want him to say, 'You did good,' and for him to come and say, 'You did good' means everything."

Read more about the career of playwright Neil Simon in the Playbill Vault. 

The not-for-profit TACT is "dedicated to presenting neglected or rarely produced plays of literary merit" that have not been seen in New York in 20 years or more. Its co-artistic directors are Evans, Cynthia Harris (who plays Grandma Kurnitz in Lost in Yonkers) and Thompson.

Read Playbill.com's earlier coverage of TACT's Lost in Yonkers. Lost in Yonkers continues to April 14. Several performances have been added to the run. For more information, visit tactnyc.org.