Mary Badham, the actress who played the young Scout in the 1962 movie adaptation of Harper Lee’s “To Kill a Mockingbird,” will give voice to that character again to celebrate the publication of Ms. Lee’s second novel, “Go Set a Watchman.”

Ms. Badham will appear at the 92nd Street Y’s Poetry Center in Manhattan on July 14, when the new book goes on sale. She will read from both “To Kill a Mockingbird,” which is narrated by Scout and set in Depression-era Alabama, and “Go Set a Watchman,” which features Scout 20 years later, returning home from New York. Ms. Badham received an Academy Award nomination for best supporting actress for her performance, and developed a close friendship with Gregory Peck, who played the lawyer Atticus Finch, Scout’s father.

“At age 10 I wasn’t aware of the impact ‘Mockingbird’ had at the time, or the impact the film would have later, but it has been a special part of my life ever since,” Ms. Badham said in a statement. “Now I am really excited about ‘Watchman’ and being able to share it with Miss Nelle’s loyal and passionate fans,” she added, using the name that family and friends call Ms. Lee.

The event, which will be streamed at 92Y.org/harperlee, is one of dozens of “Watchman” celebrations taking place in bookstores, theaters and libraries across the country on July 14 to mark the publication of another book by one of the United States’ most celebrated and enigmatic authors. The release of “Go Set a Watchman,” more than 50 years after Ms. Lee was propelled to fame by the success of “To Kill a Mockingbird,” promises to be one of the biggest publishing events of the decade.