The 39-year-old actress and fiance Martyn LeNoble welcomed daughter Sadie Grace into the world on January 27 and Christina revealed filming her new show `Up All Night` with Will Arnett was difficult because she hated leaving the baby.

She told People: "It`s a really hard thing to do because you miss them. But I`m doing well.

"Parenthood just changed me in the sense that nothing really matters but [Sadie].

"None of it really matters. The importance I placed on things prior to this moment, they don`t matter anymore. All that matters is I get to go in there in the morning and see her face. She smiles at me and my life is better."

Christina has previously revealed she was so overcome with emotion at giving birth she lost all her inhibitions.

The actress - who underwent a double mastectomy after being diagnosed with breast cancer in 2008 - didn`t think twice about removing her gown to lay the baby on her chest to bond.

She explained: "I dropped my gown, which I don`t do. This part of my body is very private to me. That`s a real private place. A place that I don`t have a good relationship with, let`s say.

"But at that moment of pulling Sadie out, I just tore that thing off. There`s a room full of people that I don`t know. Nurses and doctors. And she and I just laid there. It was the best thing that`s ever happened to me."
sections: Celebrities