Model Salem Mitchell takes us inside Rihanna's Savage X Fenty campaign shoot

Salem Mitchell was driving back to her hometown of San Diego last January when the freckled-faced model found out she'd be one of several models featured in Rihanna's new campaign to promote her line of lingerie, Savage X Fenty.

"It was the first month of the year and I hadn’t done anything. I hadn’t gone to any castings. I wasn’t shooting anything," Mitchell, who's days away from turning 20, told "Good Morning America."

"I wasn't necessarily stressed, but I just saw all my friends doing things [and I thought] 'Man, I’m sitting at home not doing anything,'" she said.

Mitchell didn't let her FOMO stop her. She instead decided to "get the ball rolling" and planned a photo shoot with a local photographer she knew. On set, her makeup artist asked her, "Are you under contract with anybody because I would like to use Fenty Beauty on you?"

Her response? "Use as much Fenty Beauty as you want."

While driving back, reflecting on how her photo shoot went, Mitchell received a call from one of her agents, Sarah Salem -- no relation -- who told her Rihanna's people had called. They wanted Mitchell in the singer's upcoming Savage X Fenty campaign later that month in London.

"What are the odds of that happening to me? I could not believe it either," the model said.

Mitchell, who now lives in Los Angeles' Sherman Oaks neighborhood, has made her career from finding opportunities in nascent spaces. In fact, she was discovered on Instagram after being the target of cyberbullies, who attacked her freckles.

If you haven't seen the baby-faced, 5 feet 6 inches tall model, her face is covered in the soft brown spots.

Mitchell told "GMA" she was "confused" by the bullies' comments. "I didn’t really think it was that big of a deal," she said.

"I look just look my mom and I really like my mom and she’s super stylish," she explained, adding that she felt "pretty normal" growing up "with someone who looks just like me."

It was Jan. 17 or 18 -- Mitchell can't remember -- when she arrived in London for the three-day photo shoot. On day one, Mitchell had fittings where the Savage X Fenty team dressed her in a Microfiber T-Shirt Bra with matching Lace Cheeky underwear in Caviar, or for us fashion lay men, the color black.

Over the next two days, Mitchell would pose in front of a still camera and later, a video team would capture how she felt.

"It wasn’t just about my body. It was about what I wanted to say as well," Mitchell said.

Although the model has previously worked with R&B singer SZA and has also worked in campaigns for Gucci, The Gap and American Eagle, Mitchell was still nervous walking into the shoot.

She couldn't shake her nerves as she wandered through the dark set as music played overhead. That's when someone offered her something to eat. Even though she'd have to go on camera later, she took the offer -- deciding to eat cauliflower soup and broccoli. "Just veggies," she reasoned.

Slick Woods, the bald, gap-toothed model who is now the new face of Mercedes-Benz, saw Mitchell sitting on the couch.

"She sat down across from me and said, 'Hey, are you nervous?' I said, 'Yes, I am.' She was like, 'Well don't be. It’s going to be a really fun day,'" Mitchell recalled.

"When you have role models, you expect them to be intimidating, but she offered me that support. It was really special to me," she added. "I just thought that was super sweet."

Mitchell, Woods, Jazzelle Zanaughtti, Lulu Bonfils, Stella Duval and Audrey Ritchie were among the models featured in the lingerie line's campaign, along with other models of all ethnicities and body types, including a pregnant model.

The diverse casting is in line with Rihanna's 'come one, come all' beauty philosophy. She was praised last year when she released Fenty Beauty, which offered 40 different shades of foundations.

Even Mitchell noticed how inclusive the campaign was. On set she thought: "This is major."

"There were so many types of bodies and so many types of women being visible. It was the first time I’ve seen a pregnant woman shooting lingerie," she said. "I’ve never seen that. It’s really groundbreaking and it’s nice to be a part of it. When we talk about this campaign in 10 years ... I can say, I was part of it."