A woman locked in a contentious divorce with her bond-trader husband took a Picasso off his wall — and replaced it with a forgery she made herself.

Sue Gross didn’t wait until she and Wall Street titan Bill Gross had finalized their split, swapping out a 1932 Pablo Picasso painting entitled “Le Repos” hanging in their bedroom with her own rendering.

The original is expected to fetch as much as $35 million at Sotheby’s Monday evening.

The painting, which depicts ­Picasso lover Marie-Thérèse Walter, had belonged to them jointly. But a coin flip in August 2017 — amid the couple’s divorce proceedings — awarded Sue full custody of Picasso’s depiction of his sleeping mistress, which the couple had owned since 2006.

After the flip, Bill Gross tried to make arrangements for the piece to be transferred from his ­Laguna Beach, Calif., house to his ex-wife, sources told The Post.

But the ex-Mrs. Gross said that was unnecessary — she already had taken the real thing.

The couple’s art collection had been appraised by Sotheby’s in January 2017 amid the divorce proceedings, but Bill learned only later the Picasso was appraised in a different location than Laguna Beach.

“Bill was shocked Sue already had the piece,” a source said, adding that Bill said, “She stole the damn thing.”

In November testimony, the ex-wife readily admitted to swiping the Picasso, citing an e-mail Bill sent to her where he instructed her to “take all the furniture and art that you’d like.”

“And so I did,” she said.

But it wasn’t quite that simple, as testimony revealed the ex-wife’s prowess for both painting and artful deception.

“Well, you didn’t take it and leave an empty spot on the wall, though, did you?” lawyers for Bill Gross asked.

“No,” Sue responded.

“You replaced it with a fake?” the lawyer asked.

“Well, it was a painting I painted,” Sue responded.

“A replication of the Picasso?” the lawyer asked.

“A replication, yes,” Sue answered.

“And it had the Picasso signature and everything, didn’t it?” the lawyer asked.

“Not exactly . . .” she said.

“Whose signature was it? Sue Gross?” the lawyer asked.

“I don’t remember how I signed it. Bill will remember because I painted it at home years ago,” she said.

“Did you tell him that you took the Picasso?” the lawyer asked.

“No. We didn’t speak for a year and a half,” she answered just before the line of questioning turned to a 7-foot, 300-pound rabbit sculpture she also admitted taking.

But the Picasso’s disappearance shouldn’t have been a total surprise for the bond king. Bill Gross had said that several items disappeared from the house, such as a Tiffany clock, 20 bottles of wine, Christmas decorations and a 1,000-pound-statue, The Orange County Register ­reported in October.

Gross also had previously praised his ex-wife’s painting ability. In a June 2015 investor outlook letter for Janus Capital, where he now works, Gross admitted that his then-wife was “the artist in the family.”

“[Sue] likes to paint replicas of some of the famous pieces, using an overhead projector to copy the outlines and then just sort of fill in the spaces,” Gross wrote.

“’Why spend $20 million?’ she’d say — ‘I can paint that one for $75,’ and I must admit that one fabulous Picasso with signature ‘Sue,’ heads the fireplace mantle in our bedroom,” Bill continued, referring to a different artwork.

The Gross divorce was finalized on Oct. 6, 2017.

Lawyers for Sue did not respond to multiple requests for comment. Reps for Bill Gross declined to comment.