Mary-Kate and Ashley Olsen say they "don't trust a lot of people" in their fashion ventures.
The 25-year-old designers say they prefer to take matters into their own hands when it comes to working on their fashion lines including The Row and Elizabeth and James.
While their hands are full with many projects they admitted it's easier tackling their ventures as a duo.
"We are perfectionists," Ashley told British magazine Elle. "We always wanted to be closely involved with everything, totally hands on - that's why it works. If we step away, it stops working."
Mary-Kate added it was a big responsibility but "we've been doing it for years."
"I know it sounds controlling, but that's how it has to be," she said.
The pair do everything together as a team but refuse to share certain clothing items. The siblings get overprotective about their wardrobes at times.
"There are some items we get a little possessive about," Mary-Kate admits.
Mary-Kate and Ashley also confessed that they aren't fashion obsessed despite their love of clothing.
"I sometimes wear sweatpants on a plane," Ashley said before her sister added, "I'm not very aware of trends or hot new items. We're not cool."
The twins now hope to open their own retail store and expand their ventures into fragrance and designing furniture.