Kate's custody battle with ex over son

Kate Hudson and her ex-husband, Chris Robinson are reportedly at war over custody of their eldest son Ryder.

The pair have held joint custody ever since their divorce in 2007, when Ryder was just two, but according to the Daily Mail, Black Crowes frontman Chris has filed a petition to re-open the case.

Listing Kate, 37, as the respondent, the 50-year-old is believed to have submitted documents to California’s Superior Court, calling for both parents and their son to undergo evaluation.

The document reportedly states that, “The evaluator shall perform a child custody evaluation and issue a written report and make recommendations for use by the parents and the Court in developing a parenting plan that addresses legal custody and physical custody, including where the child shall reside and visitation orders based upon the best interests of the child.”

As part of the evaluation, the couple have also agreed to grant the court access to their health and mental health records, and have agreed to submit to drugs, alcohol and psychological testing if deemed necessary.

The document demands the 37-year-old Almost Famous actress pay the initial fee deposit of $7,500 for the evaluation.

If Kate and Chris fail to reach a settlement by June 30 this year, the court will impose a decision.

The blonde beauty and her muso ex parted ways in August 2006, with Chris filing for divorce in November that year amid rumours she was having an affair with You, Me and Dupree co-star Owen Wilson.

Since then, Chris has found love with third wife Allison Bridges and the two have seven-year-old daughter Cheyenne.

While Kate got engaged to Muse singer Matt Bellamy in April 2011 only to split in 2014. The couple share five-year-old son Bingham.

Since then, The Divorce actress has been linked to a number of men, including Dancing With the Stars’ Derek Hough and singer Nick Jonas, with the latest being Angelina Jolie’s estranged beau Brad Pitt.

They've apparently been keeping their romance under wraps while Brad goes through his own custody battle with Ange.

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However, last month, Kate was reportedly overheard confirming their fling to friends at two Golden Globes after-parties, with Woman's Day claiming she told one group they'd rendezvoused on "several occasions".

The Bride Wars star has also previously revealed on the Howard Stern Show that she thought Brad was "very, very handsome" when the radio host pressed her on who she'd like to date now she's single during an interview late last year.

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