Brian Doben/People

To celebrate her promotion, Kotb posed for the cover of People's Jan. 15 issue (on sale Friday). "When you click with someone, man, woman, it doesn't matter. If it works, it works," she said of her natural chemistry with Guthrie. "We're sort of like sisters, and everybody wants a sister."

"There's so much of this that was unexpected. But what's really cool about this is just getting to get up everyday and do the things you love to do with your really good friend who you trust and love and enjoy," Guthrie added. "Our biggest problem is that we actually talk about other things all throughout the show. Sometimes we're like, 'OK, pay attention. Do your jobs ladies!'"

The duo also discussed how difficult it was to break the news of Lauer's firing—live and on-air. "That morning was so hard, but Hoda and I were in it together," Guthrie said. "We are family, and families do go through hard times, and when that happens in good families, you just get closer...It was such a shock to wake up one day and not have Matt, but it was the most natural and comforting thing in the world to have Hoda right there. No one wanted that to stop." Kotb substituted as Guthrie's co-anchor until before the holidays, when NBC execs made a job offer.

Throughout the transitional month of December, Kotb insisted she never considered whether she would permanently fill Lauer's chair. "We were just trying to make it through those days together," she said. "Sometimes when you go through something with someone, you see something special. I think that's what happened. I didn't think about whether it would be me."