The 'Let's Get Excited' star will present the awards show with Radio 1 DJ Reggie Yates in Liverpool next month.
"I hosted it years ago with LL Cool J. I've performed with Mis-Teeq so for me it's like coming home," OK quotes her as saying.
"I don't even think the show is about music of black origin anymore. It's just about great British music."
This year's nominated acts include Tinie Tempah, who is up for four prizes including 'UK Act' and 'Best Song' and N-Dubz, Dizzee Rascal, Professor Green and Plan B, who are each up for three awards at this year's ceremony.
The MOBOs takes place on October 20.