Erica Cerulo and Claire Mazur are work wives. They’ve been friends ever since they met at the University of Chicago in 2002 and their intertwined personal and professional lives has helped them thrive in business. They gave toasts at each other’s weddings, they’ve shared the experience of having children, and co-founded Of A Kind, their own fashion business, which blends retail and editorial content.

Mazur and Cerulo, who have been friends for 17 years and business partners for nine years, noticed a lot more women sharing relationships similar to theirs. They decided to dig deeper and research the work wife trend. The pair joined YFi AM to talk about their new book, “Work Wife.”

“In putting together the book, the research that we found was that people who have a work best friend are seven times more engaged with their work and produce better work,” says Erica Cerulo.

According to Gallup, women are more than twice as likely to be engaged when they have a best friend at work (63%) compared to women who don’t (29%).

The work-wife relationship that Cerulo and Mazur espouse is one where opening up about your personal life enhances your professional life. It only requires the willingness to be vulnerable.

“We live in an era where you are responding to emails at home at night,” says Mazur. “You can’t pretend that there is this divide between the personal and professional. It’s all personal, it’s all professional, and being able to come to work and say, ‘hey was up all night last night with a crying baby, if I seem a little off it’s not because I’m not invested in the work, it’s because I have this thing going on at home.’ That’s such a boon.”

Cerulo and Mazur, who gave toasts at each other’s weddings, say their work relationship is one of their proudest achievements.

“Our professional partnership…is so anchored by our friendship,” Mazur says. “We are able to be our whole selves at work. Because we have this relationship that really benefits from the emotional transparency, the vulnerability, the compassion, that we bring to our friendship which is a really productive sort of culture to bring into the office place.”

Arguably one of the most successful work wife relationships of all time is the partnership between Olympic gold-winning volleyball champions Misty May and Kerry Walsh. Mazur and Cerulo spoke to them for their book.

“One of the things that Misty talked a lot about was understanding when your partner is having a bad day, and just can’t get the ball up,” Mazur says. “You’ve just got to say to her, I’m here for you, I’ve got it, you just worry about getting the ball to me and I will get it up for you.”