Luisa, 25, and Leah, 24, last night saw off competition from Neil Clough, Jordan Poulton and Francesca MacDuff-Varley following the notorious interview stage of Lord Alan Sugar's competition.
But although both girls are desperate to win, it appears they have formed a very close friendship away from the cameras and the boardroom.
Taking to Twitter last night, Luisa said: "Me and my #apprentice bestie @DrLeahTotton - I love this girl, couldn't think of a better person to be here with #GirlPower."
She added: "To all my business barbies out there, remember, when in doubt smile and pout!!"
Luisa Zissman (@TheLuluLife) July 10, 2013
Luisa had previously described her fellow competitor as "Auntie Leah" when speaking about her close bond with her daughter Dixie.
Following Monday night's episode of The Apprentice: The Final Five, which featured photos of Luisa and Dixie, Leah tweeted: "Aww Lu with her daughter Dixie!! Soft side of @TheLuluLife that u don't see on the show xxx"
Luisa then replied: "@DrLeahTotton ah thanks angel, Dixie loves you too #auntieleah."
Meanwhile, Leah has also thanked fans for their support after the nail-biting semi-final. She tweeted: "Thank you for the lovely tweets, I'm so happy! The Apprentice final - can't believe it! So so happy! Xxx"
At the end of last night's show, Lord Sugar's righthand woman Karren Brady turned to him and said: "I can't tell you how pleased I am that your new business partner is going to be a woman."
We're sure plenty of viewers will agree with that!