Susan Graham, one of the world’s most beloved sopranos, returns to sing Mahler’s Third Symphony with the Boston Symphony Orchestra and the Tanglewood Festival Chorus, under the direction of Andris Nelsons, at Tanglewood on Friday, August 24, at 8:00pm.

Have you ever wondered what soloists do in the minutes and moments prior to performing in front of thousands?

Graham took some time from her rehearsal schedule to share her “preflight check list.”

“I always do high kicks in the wings,” Graham says. “Even if I’m in a long dress, I hike that sucker up and do high kicks for four minutes.

“That’s because if my hips are locked when I’m standing, then everything else feels locked.”

Graham says that backstage workers around the world are no longer surprised by her high kicks.

She will then swing her arms in big circles so her ribs, her back, and her chest feel fluid, and then she will drop her shoulders and roll her head around.

“I’ll take some deep breaths to make sure my breath is low, not shallow,” she says. “And then I’ll lift the tip of my thumb and rub it on my soft palate, to remind my soft palate to remain high, wide, and soft for the next hour.”

Graham recently performed a run of The Merry Widow at the Met.

“Ten minutes before I go on,” she says, “the rest of the cast are waltzing their feet off. I’m back there on a ladder, with one foot on the ground and another on the fourth or fifth step, doing ballet bends and stretches, so I can go out there and waltz and not look like Frankenstein!”

Graham says that she wears elbow-length gloves as part of her costume in The Merry Widow, and nevertheless, “I did the same thing with my thumb, in the glove,” she says. “I had to make sure my soft palate would be right. And then I wiped the spit off—you’ve got to shake hands when you’re out there!”

Saliva is an occupational hazard for professional singers, she says, or in her own words, “Every singer I’ve ever sung next to is like the Niagara Falls of spit. It’s what we do.”

When it’s time to go out on stage, she says she takes “a big, deep breath, and I smile and smile, because I’m so happy to be there.

“Every time I walk on stage, I feel like I’m having a party in my own room, and I’m the hostess.”

Graham makes it a point to smile at the chorus, and then as she’s walking through the orchestra, she touches the players on the shoulder, and then takes her spot, typically to the right of the conductor.

“I’ll shake hands with the concert master, who represents the entire orchestra, and then I’ll either sing or sit down and wait for my turn.”

Ever wonder what soloists are thinking about when they are waiting to sing?

“It always amuses me,” Graham says, “but the audience thinks it can’t be seen. There’s a guy in the front row, reading a newspaper. Someone else is sleeping, and someone else is talking to his neighbor during the softest part of the music. Today, people are checking their phones and texting.”

Aside from the rudeness of it all, Graham says, people don’t give themselves permission to enjoy the music.

“People are so serious at orchestra concerts,” she says. “You might have a little romp through the forest in Mahler, or some military-sounding music. And yet, most people just sit there stone-faced, not smiling, not swooning, not tapping their feet. I never understand that.”

And then when her entrance approaches, Graham realizes “that it’s time for me to attempt to add to the glory of everything that’s going on. Until then, I’m watching my colleagues, because each has his or her own physicality, mindset, or expression.

When it’s her turn to sing, Graham says, “the first goal is to get out of your chair gracefully. Then I need to make sure that my score is at the right page—it usually is—and then I mentally go through the first few bars of my first entrance.

“My feet are about a foot apart, with my weight equally balanced, and my shoulders are down and back, and my head is at the right level. When I take my breath to start singing, I do so with the first word in mind, so that the shape of the vowel is already there.”

For Mahler’s Third, Graham’s first words—“O, menche” are “lowish in my register, so I have to make sure that I’m not opening my mouth too wide, so I don’t cut down on the resonance in the back of my mouth.”

And then, when actually singing?

“It’s really about listening and feeling,” she says, “because we can’t hear ourselves in the way that we actually sound. In a hall as responsive and brilliant as Boston Symphony Hall [where Graham sang Mahler’s 3rd Symphony this past January], I can usually tell how the resonance is going. Some places are not that responsive; Symphony Hall in Boston is.”

And what about the singing itself?

“I try to express the text with my heart and bring the right expression to it,” she says. “As I always say to young singers, say what you mean and mean what you say with every sound that comes out of your mouth. Attach a meaning to it.

“Our instrument is the human body. We are human beings communicating with other human beings, and it’s a visceral experience.”

Graham explains that visceral doesn’t always mean pretty.

“In recital,” she says, “I have a Spanish song about grief, and it’s actually a wailing sound. It’s not what any singing teacher would call great technique, but that’s what’s called for, and that’s what I do.”

Graham says that when she doesn’t feel well, then, “it’s just about survival. If I’m feeling a cold, or if my throat isn’t right, or if it’s tired, or if I’m coughing, I need to take emergency measures. I have to narrow the sound even more. I call it threading the needle, because the sound becomes so tiny and it has to go through a tiny space to be more efficient. We’ve all had days like that.”

What about the act of singing in front of thousands?

“Sometimes I think, this is the strangest job on the planet,” she says with a laugh. “I’m standing in front of thousands of people…and doing controlled screaming, with no compunction, no reservation. And then once I get over that thought, I remember, as I always do—that I’m the luckiest person in the world.”