In the Johannesburg City Hall, a special audience member got a private cello solo: “Twinkle Twinkle Little Star.”

Richard Belcher crouched down to play it for his son, Finn, who’s 14 months old. Cecilia Belcher, Finn’s mother, was warming up on second violin onstage.

Along with the musicians, choir members, board members and tagalongs on this South African tour are a handful of tiny guests.

Cecilia Belcher joined the orchestra in 2014, becoming its assistant principal second violin last year. When she heard about this tour, “I thought, I wouldn’t miss this for the world,” she said. “And I wasn’t going to be separated from Finn. So he had to come!”

So here he was, in Johannesburg, bouncing to the quick beat of Leonard Bernstein’s “Overture to Candide” on his grandmother’s lap.

For touring musicians who have kids under 2 years old, the orchestra pays for a caregiver’s flight and hotel. Finn has been on a safari, a peninsula tour of Cape Town and a wine country excursion.

And he’s heard a ton of music. At the Pretoria concert, they sat in the back “where we could escape,” said grandmother Marilyn Lorenz-Weinkauff, who lives in St. Louis, Mo.

“While we were rehearsing, he was popping, rocking and dancing,” Belcher said, holding Finn on her hip. “He clapped when we finished. So I think he’s listening.”

The other musicians have been a huge help, his parents said. “Everybody has offered to carry things for us and pack things in their trunks, extra diapers,” Belcher said.

“We’ve had about 50 short-term babysitters who are wanting to hold him for a little bit,” said Richard Belcher, who isn’t an orchestra member but is subbing as a cellist for the tour.

“I think it’s nice, throughout the tour, just to have a smiling baby,” Cecilia Belcher added. “It brings everybody’s spirits up.”

As she spoke, violinist after percussionist after bassist stopped by to smile, play peekaboo or tickle Finn.

“What an experience. Everybody knows him,” said Lorenz-Weinkauff. “A lot of these people have kids who have grown up in the orchestra.

“It’s a community. It’s family.”