The 4 PM "Closing Party" is scheduled to feature Brown at the piano with special guests Adam Pascal, Lara Pulver, Graham Phillips and Nita Whitaker. The Theater Geeks of America will also take part in the event.
Brown won a Tony Award for his score to Parade and also wrote the scores to The Last Five Years, Songs for a New World and 13. His solo recording is titled "Wearing Someone Else's Clothes."
The afternoon, according to the Festival's website, will be held in "Noelle and Tom Hicks' gorgeous garden."
Tickets, priced $175 per person ($75 for students), are available by visiting http://lafestival.org.