Singer Monica Refusing to Talk Shannon Brown Divorce on T.I.'s Reality Show

Monica is clamming up when it comes to questions about her divorce with ex-NBA baller Shannon Brown ... and it's pissing off producers on T.I.'s reality show.

Sources close to production on "T.I. & Tiny: Friends & Family Hustle" tell TMZ ... Monica is refusing to talk about calling it quits on her marriage, and she won't even mention her ex-husband's name.

We're told Monica's decision to stay mum is frustrating the people tasked with crafting an interesting storyline for the singer ... and she's just not cooperating with producers begging for her to open up about her relationship with Shannon.

The trailer for the reality show's upcoming season makes it seem like Monica's an open book when it comes to her divorce ... but we're told that couldn't be further from the truth. In the trailer, she says she never imagined being a single mother in her 30s -- but that's all you're gonna get outta her.

We broke the story ... Monica filed for divorce from the former pro athlete back in March, after 8 years of marriage.