The singer, who quit the BBC show after the last series, has been replaced in the coaches line-up by Kylie Minogue.
The next series, which also sees Kaiser Chiefs frontman Ricky Wilson join Kylie, Sir Tom Jones and Will.i.am as coaches, starts tomorrow.
Jessie said she left the show, known for its trademark swivel chairs and blind auditions, so she could write more music.
She said: "That's one of the reasons I'm not doing The Voice. I want to focus on the music and getting an album out in the US which is my priority right now but I'm excited to watch it as a fan.
"I said I'm going to buy a cheap Ikea chair, a red one, and play by myself at home and just see what happens and shout at the TV 'Pick me'."
The Price Tag star, who was nominated for a Brit Award for British female solo artist last night, said she was excited to see Kylie on the show.
She said: "I definitely will miss it, I'll miss Tom, I love Tom and Will's craziness, never knowing what he's going to say.
"I feel like it's really fun to take a step away and see what they've done."