Performing with The Tabernacle Choir at Temple Square has always been on Kristin Chenoweth’s “bucket list.”

But she acknowledges, with sold-out concerts coming Thursday, Friday and Saturday nights at the Conference Center in downtown Salt Lake City, she’s laboring a bit — with the Utah air.

“I have struggled. I’m not going to lie,” she said Wednesday at a news conference in The Church of Jesus Christ of Latter-day Saints’ Relief Society Building. “I’m like, ‘C’mon, get your breath!’”

Rehearsing on Tuesday night, she found herself having to take breaths in the middle of lines.

It’s not just the smog, which cleared with Wednesday’s snowstorm but is forecast to return by Friday. The altitude is making it tough on the Tony- and Emmy-winning actor/singer as she prepares for the performances.

“I went to the mall the other night,” Chenoweth said. “I took a walk there, and I thought, I’ll be fine.” But she found herself struggling to draw breath — because of the altitude and the bad air.

“They did tell me about the smog, so I’m really trying to be aware and just forgive myself a little bit. And acclimate,” Chenoweth said. “And then I wake up today and this [snowstorm] happens? It was a Christmas miracle!”

But concertgoers don’t need to worry. “I’m going to nail it,” she said with a laugh.

Chenoweth — a gay rights activist — has faced calls to drop out of the concerts because of the church’s history of opposition to same-sex marriage and other issues. That subject did not come up at the news conference, but she was wearing a lapel pin signifying her support for the LGBTQ community.

Tabernacle Choir musical director Mack Wilberg said he’s pursued Chenoweth for a decade to perform in the Christmas program, and she said she’s thrilled it finally worked out.

“It’s been a long time going, and all I want to do is celebrate the reason for the season” and the music, she said, which is “part of my DNA. And I’m so honored to get to share the stage with you, Mack. To be here with you guys. We’re making music and celebrating the birth of Christ.”

Chenoweth will be having a bit of a family reunion backstage. “Two of my aunts are flying in from Oklahoma to see the show," she said, “and that’s going to be extremely special for me.”

As always, Chenoweth was filled with energy. She playfully punched Wilberg as the news conference was beginning; she may be the only star ever to act disappointed when there were no more questions.

“When she comes up and she gives Mack a big hug or a punch on the shoulder, she means it and she feels it and it’s exciting,” said Tabernacle Choir President Ron Jarrett. “Other artists have been much more reserved.”

“I don't know if we've ever had as versatile a performer as Kristin,” Wilberg said. “She not only is a classical singer, but she does pop. She sings country.”

All of which will be part of the program, details of which are being kept under wraps.

“We were are just all completely overwhelmed and charmed by the incredible energy that she brings to the stage,” Wilberg said.

In this case, she’ll be onstage in the massive Conference Center, which seats 21,000.

“It's very overwhelming when you walk out,” Chenoweth said. “It has this massive feeling, yet intimacy.

“I pretend-fainted last night because I didn’t know what to do with it,” she said — going on to describe these as “champagne problems.”

Chenoweth said she’s facing one other local challenge, the result of a “situation that happened in the dressing room involving pizza.” From The Pie Pizzeria.

“Are you kidding?” she joked. “I’m trying to then try to fit into the beautiful Christian Siriano gowns after that? Thanks.”