Leah was the runner up on last year's show and this series will see Will.i.am invite her back to inspire his latest crop of singers.
Once again Will was also joined by original member of the Black Eyed Peas Dante Santiago to help him train his acts ahead of the next stage.
In the battles, the coaches will have to pitch their acts against one another in a series of head to head musical battles.
The coaches will give the artists song that they must duet on before mentor both competitors both together and separately ahead of the performance.
One winner will be declared in each pairing leaving six acts in each team but there's an extra twist again this year with the Steals.
Each coach will be able to add a seventh act to their team by selecting one of the singers that their rivals has rejected.
It all starts this Saturday night from 7PM on BBC One.
Browse pictures of Team Will in training for the battle rounds with Leah and Dante below...