Nicole Kidman disclosed the secret behind her “successful marriage” to her estranged husband, Keith Urban, just months before they ended their relationship.

“We have a double shower,” the “Big Little Lies” star cheekily told W magazine in January.

“The double-headed shower: key to a successful marriage.”

Kidman, 58, emphasized that “separate commodes” in their primary bathroom were also helpful.

The actress and Urban, who is 57, have stopped using the same bathroom, with Page Six announcing on Tuesday that they have split after 19 years together.

“Sometimes relationships just run their course,” an insider told us.

We’re told Kidman “did not want the separation and was trying to save things,” and that she feels “betrayed.”

Furthermore, sources informed TMZ that the former couple has been living apart “since the beginning of summer,” and Urban reportedly acquired real estate close to their family residence in Nashville, Tennessee.

The country singer is currently on the road for his “High and Alive World Tour,” while Kidman has been caring for their daughters, Sunday Rose, 17, and Faith Margaret, 14.

Kidman officially filed for divorce on Tuesday, one day after news broke of her and Urban’s split.

Court documents obtained by Page Six revealed that the “Family Affair” star stated the breakup was due to “irreconcilable differences” and listed their separation date as Sept. 30.

Kidman requested to be the “primary residential parent” of her and Urban’s daughters, and to have custody of them for 306 days out of the year.

The “Holland” star also asked the court for herself and Urban to be permitted to make “major decisions” together when it comes to their children.

TMZ reported Urban has already moved on with a new woman, though he has not responded to the rumors.

Kidman and Urban, however, potentially hinted at their marital woes with interview and social media brush-offs earlier this year.