Brown, 37, is in the final stages of securing a seat next to Howard Stern and Howie Mandel. The British performer is replacing longtime judge Sharon Osbourne, who left the show after a public feud with NBC over her son, Jack's, involvement with another reality show on the network, "Stars Earn Stripes."
At the time, Osbourne accused NBC of declining to cast Jack after discovering he had been diagnosed with multiple sclerosis.
Back in December, Rosie O'Donnell had confirmed that she was "talking" to NBC about joining the reality competition show and was "very interested" in the gig.
This isn't Brown's first time at the judges table. She served as a judge on "The X Factor Australi"a in 2011, guest-judged the U.K. "X Facto"r following Kelly Rowland's departure, and also judged Britain & Ireland's "Next Top Model."
After competing on Season 5 of "Dancing with the Stars" in the U.S., she also hosted the Oxygen weight loss series "Dance Your A-- Off" and starred in her own reality show on the Style network, called "Mel B: It's a Scary World."
She also reunited with the rest of the Spice Girls for a performance at the 2012 London Olympics last summer, and a Broadway show based on their music is in the works.