Eminem's marriage was said to have been volatile

The drugs were found by an officer arresting Kimberly Anne Mathers for driving with a revoked licence, police said.

She was released pending further investigation, and no formal charges were filed, said police in St Clair Shores, Michigan.

Ms Mathers was arrested on Tuesday after being pulled over by police on the eastbound Interstate-94 road, St Clair Shores police said in a statement.

An officer found the suspected cocaine in Mathers' car and on her person Police statement

She was stopped after failing to change lanes to move away from an emergency vehicle parked on the hard shoulder, the statement said.

It added that following her arrest, "an officer then found the suspected cocaine in Mathers' car and on her person".

Ms Mathers divorced Eminem - real name Marshall Mathers III - in 2001 following a reportedly stormy marriage.

They married in June 1999 and had a daughter, Hailie Jade.

Nightclub row

Eminem has rapped in his songs about killing his former wife, leading to accusations that he dislikes women.

On the track '97 Bonnie and Clyde, one of his most controversial lyrics, he talks of putting her body in a trunk.

In December last year Eminem's grandmother told a newspaper that the couple had reconciled and Ms Mathers had moved back into his Detroit home.

In 2001, Eminem was given two years' probation after a confrontation with a man he believed he saw kissing Ms Mathers outside a nightclub. He had admitted carrying a concealed weapon.