Powell, who previously represented Andre's ex-wife Katie Price, has reportedly agreed to work with Katona under the condition that the star takes weekly drug tests to prove she is no longer using cocaine.
It is thought that Katona is also under strict instruction to avoid all contact with her estranged husband Mark Croft, who she dumped last month in an infidelity row.
Powell told The Sun: "Kerry knows this is her last chance. There will be no drugs and no Mark. She has signed a legal document agreeing to that."
She continued: "Kerry approached me six months ago to take her on but I refused while Mark was still around. I do not believe he has been a positive influence on her. If she is prepared to work hard and stay clean she has a great career ahead of her."
Sources claim that Katona is desperate to turn her fortunes around following a series of scandals and hopes to be back on television by the summer.