Kim Kardashian Reacts to Kylie Jenner's $600 Million Deal (Exclusive)

Kim Kardashian West couldn't be prouder of her youngest sister, Kylie Jenner, when it comes to Kylie's recent boss move.

Kim Kardashian West couldn't be prouder of her youngest sister, Kylie Jenner, when it comes to Kylie's recent boss move.

ET's Lauren Zima spoke to Kim on Wednesday about her new shapewear line, SKIMS, and the 39-year-old reality superstar also reacted to cosmetics brand Coty recently acquiring 51 percent of Kylie's brands, Kylie Cosmetics and Kylie Skin, for $600 million. Kim revealed that it had actually been Kylie's plan for a year to sell half her business.

"I've known that selling her business was always in the works for her for a long time," Kim tells ET. "A lot of companies were bidding and really wanted to buy her brand, and so selling just about half of it was a decision that she made about a year ago and, you know, that she wanted to."

"I'm so proud of her," she continues. "To think in her early 20s, she built a business off of something that she first was insecure about and finding confidence and, you know, just tapping into that and figuring out how to make an amazing product and just being true to herself and doing what she loves to do, that's so inspiring and so amazing and I'm so proud of her."

Kim admitted that in the early days of her career, she and her famous family weren't choosy about their endorsements due to them thinking their "15 minutes of fame" would run out. But now they only choose to get involved in businesses that are fulfilling and authentic to themselves, which for Kim, is clearly SKIMS. The brand recently added body tape to its collection.

"I put my heart and soul into SKIMS," she says, noting that she would love to see Oprah Winfrey, Madonna and of course, her beloved Cher, wearing the line. "I have spent so many years sewing shapewear, dyeing shapewear, cutting up shapewear with our tape, using any kind of tape you can imagine -- gaffers tape, shipping tape, packing tape, everything you can imagine -- that would leave me with these, like, scars and burns every time I take it off. So, I really have worked hard to make everything in this SKIMS line, everything I would have dreamed existed a while ago."

As for the holidays coming up, Kim gave an update on her brother, 32-year-old Rob Kardashian. Although Rob has been private in the last couple of years, he recently made rare appearances at family events like Kim's 39th birthday party in October and Kendall Jenner's star-studded 24th birthday party on Halloween.

"He's doing great, you know, he's definitely more low-key than all of us and we love that and respect that," Kim shares. "And he'll be around for Thanksgiving. He's been around a lot I'd say. For the past year or two, he's been around, and we love having him around. He's been really good."

Meanwhile, when ET spoke with Kim as well as her sisters, Kourtney and Khloe Kardashian, earlier this month about their KKW Fragrance Diamond collection, Kim talked about possibly playing matchmaker for her single sisters. Watch the video below for more: