"Normally at a casting, you have a quick chat and they look at your book. But with a Victoria's Secret casting, they take the time to really talk to you, see how you walk and really get to know as much about you as they can in a short period of time."
But the VS-approved body doesn't come naturally to the New York based model, who puts her physique down to a combination of high intensity workouts, but nothing that will leave her burnt out before the casting call.
"For me, it's three months before the casting I need to step up my game with training, and not skipping workouts" she said.
"Last year ahead of the Victoria's Secret casting, I did two gym sessions a day. But this year I am doing less, and more focusing more on resistance and strength training which has really changed my body.
"You don't want to arrive at the casting burnt out and cranky, you want to be able to live your life and show them that on the day."
Based in New York, but splitting her time in Los Angeles - Malcolm said while cardio is good, she has seen more results with a combination of toning.
"I do a bit of boxing but I have actually shifted over to doing a workout called 'Body by Simone', which is little bits of high intensity cardio mixed with a lot of toning," she said.
"It's really changed my body, and it's found these muscles that I didn't know existed.
"What's great is that it's a lot of fun too, which I think exercise needs to be."
But along with the training comes the diet, which the blonde beauty admits can be boring at times.
"Aside from working out, I pay very close attention to the way I eat and what I eat," she said.
"I eat clean year round, so I avoid all desserts, sugars and starchy type foods.
"Leading up to the show I drink lots of water, protein shakes and vegetables. I really love to cook so I do a lot of it myself.
"I always look forward to having something other than what I'm eating leading up to a show. But it's a couple of months of my life, and it's so worth it so I'm willing to make that sacrifice to be able to walk with Victoria's Secret again."
Malcolm described behind-the-scenes of the show as "total craziness", but that "the whole atmosphere is really fun and really uplifting".
"Picture a room full of hair and makeup tables full of girls," she laughed.
"Kendall and Gigi are super nice normal girls. I didn't have too much to do with Kendall, but Gigi was in the same section as me. She's such a sweet girl and super unaffected by all her celebrity."
Malcolm, who was this week named the face of Australian swimwear brand, Seafolly's 2017 campaign, said while this lifestyle is part and parcel of being a model, being part of the Victoria's Secret family is a dream come true.
"All the girls look amazing, they are all beautiful people," she said.
"With Victoria's Secret it's about confidence and not being afraid to talk and show people your personality.
"While it's very nerve wracking, and definitely one of the most terrifying experiences of my life, being on that runway was also one of the most rewarding experiences of my life as well."
Last year, the then 23-year-old was slammed as being too thin - and even labelled an anorexic by some of her Instagram followers - after she shared an image of herself wearing yellow lace lingerie.
One user claimed she was a "terrible role model for young girls", while another asked if she was anorexic.
"I don't feel bad, and I'm definitely not unhealthy," she said.
"I know what I do, I know who I am, I know what I like and I know that those people are hurting inside and I hope that they find some happiness really," she told The Daily Mail.
"The thing that was bothering me last year was that they were saying I had an eating disorder, and I definitely do not have an eating disorder.
"And it's quite disrespectful to people who struggle with these illnesses because there is a whole lot that goes into them."
