She's a three-time Grammy Award winning artist and the co-founder of one of the most successful pop-rock bands of all-time, but even Gwen Stefani was surprised when she was offered a role as the newest judge on NBC's The Voice.

Appearing on the season premiere of The Ellen Show alongside returning fellow judges Adam Levine and Blake Shelton, as well as other newcomer Pharrell, Stefani talked about finding out that NBC wanted her to replace Shakira on the hit reality competitions series and admitted that she wasn't sure if she should take the job so soon after giving birth to her third son, Apollo, but in the end, she knew she had to take the opportunity.

"I didn't think anything about it," she said. "I had the baby, I was sitting with my parents, I had some friends over, and the call just came in. It was so short, it was just like 'Do you want to do The Voice?' And I hung up and I was like, 'My life is so weird. What do I do?'"

"I started asking all of my friends, 'What should I do? Should I do it? Should I do it?' she added. ""I just go, 'I'm gonna do it!' And it's been so incredibly honestly, because I've done so many incredible things, but I've never done something like this before."

Stefani and Pharrell are not the first replacements for original judges Cee Lo Green and Christina Aguilera-Shakira stood in for Aguilera in seasons four and six, while Green was replaced by Usher for those seasons.

The Voice season 7 premieres Monday, Sept. 22 at 8 p.m. on NBC.

Tags: The Voice nbc Reality TV