The 39-year-old star has opened up about how the three singers were pitted against each other, but she's glad they all managed to stay true to themselves despite interference from "record labels" earlier in their career.
She told 'Entertainment Tonight': "We grew up in a very competitive environment when it came to our record labels and being pushed to do things that were unnecessary for success. Everybody has found their own way, in such a beautiful, inspiring way. I just love it that everybody has remained authentically who they are. There's so much room at the top! I mean, think about how many people are in heaven! Come on. there's a lot of room at the top and I am happy to share any top slot with anybody."
The 'Employee of the Month' actress insisted although she has "more things" she wants to achieve, following in Christina and Britney's footsteps with her own Las Vegas residency isn't on the cards.
She explained: "That is not on the bucket list. I feel like I'd have to write a lot more songs to do a Vegas residency."
Instead, Jessica admitted she'd rather have a run on Broadway, and revealed her memoir 'Open Book' means she has plenty of options.
She added: "You just never know. Right now, a lot of things are happening. 'Open Book' has opened a lot of doors."
Jessica's sister Ashlee Simpson previously heaped praise on her sibling for sharing the "truth with the world" in the memoir, in which she discussed her high-profile relationships with Nick Lachey and John Mayer, her battle with booze and how she was sexually abused as a child.
Ashlee wrote on Instagram: "I am so very proud of my beautiful, brave, kind, loving sister!!! It's beautiful to see you sharing your truth with the world. You are so inspiring. I love you so much."