The 40-year-old anchor quit the entertainment show earlier this month after 14 years at the helm and Maria, 37, has been confirmed as her replacement, after Giuliana was forced to address reports that the pair had been feuding.
Maria joins co-anchors Catt Sadler, Jason Kennedy, and Terrence Jenkins.
Earlier this month Giuliana insisted it was ''100 per cent'' her decision to quit and claimed she had been planning to move on for three years.
Asked about speculation she was pushed off the show, she said: ''It was 100 per cent my decision to leave. This has been three years in the making.
''I took on a challenge 14 years ago. I was a young reporter, and 'E! News' was my dream job. It's been an incredible journey. But after 14 years, I have nothing else to accomplish on the show. I want to grow as a person, as a businesswoman, as a host, and in order for me to grow, I need to take on a new venture and new challenges.''
Giuliana also said she has never had any issues with any of her co-workers, including Maria, who joined the network last year.
She told PEOPLE.com: ''I've never had a feud or drama with any of my hosts or co-hosts, and there certainly isn't one now. There is no feud. It takes two to feud, and I'm not feuding!''
The brunette beauty, who has son Duke, two, with husband Bill Rancic, will continue to host 'Fashion Police' and 'Live From The Red Carpet'.
His new album Underneath It All is out now.