Andrew Barth Feldman has been keeping a list of people he’ll need to call when the news comes out: that he, a 16-year-old high school junior, will be making his Broadway debut this winter as the title character in “Dear Evan Hansen.”

“It’s been so hard,” Mr. Feldman, who won the best actor award at the National High School Musical Theater Awards this year, said in a phone interview last week. “Because people are aware that I have something coming up.”

But he hasn’t been able to let the cat out of the bag.

“I have a list of all the people that I’ve lied to over the past few months,” he said. “I have to text or call or email them.”

On Jan. 30, Mr. Feldman will be taking over the role of Evan Hansen — a high school senior with social anxiety — in the Broadway musical, which won six Tony Awards in 2017, including the award for best musical and best performance by a leading actor in a musical for Ben Platt. The show currently stars Taylor Trensch. Mr. Feldman will be the first teenager to lead the Broadway cast. His audition for “Dear Evan Hansen” in July was his first for a Broadway show.