GDF Talent Show rehearsal — In this June 5, 2014 photo provided by MSG Photos, Vocal coach Marishka Wierzbicki, left, and Broadway singer Valisia LeKae, right, flank four of the students they mentored, from left, Samantha Koch, Matthew Martinez, Falyn Vega and Brittany DeLuca, in New York City. The kids will use what they learned at the annual Garden of Dreams talent show. AP

NEW YORK — Five young, amateur singers assembled a little nervously in a rehearsal room recently near Times Square. This was the day they’d be mentored by a Tony Award-nominated star.

The five had overcome things teens should never have to — cancer, stroke, pneumonia, kidney disease and a parent fighting overseas. But they were put at ease as soon as they spotted the Tony nominee’s bald head.

“I am an ovarian cancer survivor,” Valisia LeKae told them.

LeKae, who had been diagnosed late last year and underwent several rounds of chemotherapy, made the act of mentoring these kids for an upcoming talent show hosted by Madison Square Garden even more poignant.

“It definitely does because I went through Hodgkin’s lymphoma cancer,” said Falyn Vega, 14. “It’s like, ‘Wow, she went through it. I can do it too.’ It’s awesome.”

The annual Garden of Dreams talent show gives kids who have faced illness, homelessness, poverty or tragedy an opportunity to perform in front of family and friends on the Radio City Music Hall main stage. This year’s show will be held Tuesday and admission is free.

One of the children had written that she’d had the hardest time going through chemotherapy, something LeKae could relate to. “I knew exactly what she was talking about. I knew exactly what that moment felt like and the days after,” LeKae said. “But also seeing the other side of the rainbow.”

One by one, the five sang a song and waited for critiques from LeKae and Marishka Wierzbicki, a master vocal coach and associate teacher at Liz Caplan Studios in New York.

Cassie Smyth, 16, performed “Warrior” by Demi Lovato and when she was finished, LeKae congratulated her on her song choice. But Smyth, who had a stroke in 2013, had kept her eyes mostly closed.

“The great thing about being a warrior is allowing everyone to see it in your eyes,” LeKae said. “You have nothing to be ashamed of. You don’t have to keep them closed. Connect with your audience.”

The sight of Samantha Koch, 15, performing “When You Wish Upon a Star” prompted LeKae to kick off her high heels and rush over to hug the young woman who has battled kidney disease.

“When you smile, your face lights up,” LeKae said. “Smile! You are so beautiful. You have so much to be grateful for. Let them know how much joy you have.”

Vega next tackled the song of the year — “Let It Go” from the Disney hit “Frozen.” LeKae, by this time a gorgeous, dancing, animated cheerleader in a sunny romper, loved the young woman’s energy but worried that it tapered off.

Wierzbicki, who had previously coached the children to breathe more deeply and even to make swimming motions with their arms while they sang to free up their diaphragms, now counseled Vega to conserve her air.

Perhaps the biggest surprise was Matthew Martinez, 11, who stood up to perform Alicia Keys’ hit “If I Ain’t Got You.” LeKae was initially gently skeptical: “You got some soul? You’ve got a dimple that I love so it doesn’t matter.”

Then Martinez opened his mouth.

“So you do have some soul,” a visibly shocked LeKae said after he had nailed the tune. “I can just see it crawling out of you.” She counseled the boy, whose father is part of the Wounded Warrior Project, to let the song build and have a little onstage swagger.

Later, privately, she gushed: “He had this groove about him. I was like, ‘Is he married? Because I am in love.’ It was so unexpected but such a breath of fresh air.”

The last to sing was Brittany DeLuca, 16, who also played piano as she performed “Only Hope” by Mandy Moore. LeKae and Wierzbicki wanted her to let the notes settle more and to put more stress on certain lyrics.

Later, Wierzbicki said she thought all five had great potential.

“They’re deep. They know things. Some things they’re afraid of, but they have awareness and you can see that in the way they respond,” she said. “I don’t put kid gloves on to work with them because I don’t think that’s what they need.”