Jennifer Garner and Ben Affleck have taken the first step in formally ending their marriage more than a year after they publicly declared their relationship was over.

The actors both filed divorce petitions in Los Angeles County Superior Court, citing irreconcilable differences and seeking joint custody of their three children, who range from five to 11.

The filings were made without lawyers and are virtually identical. Neither lists a date of separation.

The couple announced they were separating in June 2015 after 10 years of marriage.

The actors met while making 2003's Daredevil, in which they both played superheroes

"We go forward with love and friendship for one another and a commitment to co-parenting our children," Garner and Affleck said in a joint statement at the time.

"This will be our only comment on this private, family matter."

The actors met while making 2003's Daredevil, in which they both played superheroes.

Affleck, a two-time Oscar winner, announced last month that he had recently completed treatment for alcohol addiction.

His break-up from Garner returned him to the tabloid headlines, where he had been a mainstay years earlier because of his relationship with singer Jennifer Lopez.

He lamented the renewed focus on his personal life after years of attention on his role as a parent, and the critical success of the Oscar-winning film Argo, which he produced and directed.

"This business tends to exaggerate highs and lows," Affleck told The Associated Press.

"I've had legitimate lows, movies I didn't like, and I'm very proud of the movies I directed and so on.

"But you become a cast member in a soap opera that you're not writing. You get the script every day and you find out what your role is that day."