Megan Fox and her ex-husband Brian Austin Green have had a public disagreement over an Instagram post involving their four-year-old son.

On Halloween, Brian posted a photo to his Instagram with the couple's youngest son, Journey.

The former actress commented on her estranged husband's post, saying: "Why does Journey have to be in this picture? It's not hard to crop them out. Or choose photos they aren't in. I had a great Halloween with them yesterday, and yet notice how absent they are from my social media. I know you love your kids."

Fox continued: "But I don't know why you can't stop using them to posture via Instagram. You're so intoxicated with feeding the pervasive narrative that I'm an absent mother, and you are the perennial, eternally dedicated dad of the year.

"You have them half of the time. Congratulations you truly are a remarkable human! Why do you need the internet to echo back to you what should be inexhaustibly evident in the way your children love you?"

Brian Austin Green then deleted the photo, and re-uploaded it with his son cropped out.

"Hope you all had a happy Halloween!!!" he captioned the post.

Fox and Green announced they had separated this year after 10 years of marriage. The couple began dating in 2004, and have been in an on-again-off-again relationship since.

They were engaged, then split, then engaged again, then married, then separated, then reconciled, and then now separated again, and somewhere in between, they had three children.

TheTransformersactress keeps her personal life close to her chest, but her marriage to the90210alum has been at the centre of media attention for years due to their multiple splits and three kids. Now, Megan Fox is dating American rapper Machine Gun Kelly.

Watch: Celebrities are getting creative in isolation. Post continues below video.

Here’s everything we know about Fox and Green's former relationship.

Their beginnings.

The pair met on the set of sitcomHope and Faith, when Fox was just 18 years old. The then 30-year-old Green was a father to a two-year-old son, with his former90210castmate, Vanessa Marcil.

Speaking toELLEin 2009, Fox recounted her initial attraction to Green, saying, “I was like, ‘Oh my God, I have to be with you. You’re not a threat, you’re not some d-bag that’s going to cause a lot of problems.'”

“I had to convince him that I was slightly more responsible and well-spoken and had other things to bring to the table besides being 18,” she remembers.

Brian Austin Green and Megan Fox in 2006. Image: Getty.

In 2012, speaking withCosmpolitan, the actress shared further details of their first meeting, reflecting: "The first time I saw him, I got butterflies. And the first time he casually touched me? There was so much electricity. I don't want to sound corny or cliché, but I do believe we are destined to live this part of our lives together."

The couple indeed formed a relationship and in 2007, after a three year relationship, Green proposed to Fox.

Children and countless split rumours.

The couple called off their engagement in February 2009, before rekindling just a few months later. In June 2010, they married in Hawaii.

In September 2012, Megan Fox and Brian Austin Green welcomed their first son, Noah Shannon, who is now seven years old.

"We have been very lucky to have had a peaceful few weeks at home, but I would like to release this myself before others do," Fox announced at the time.

"I gave birth to our son Noah Shannon Green on September 27th. He is healthy, happy, and perfect."

Then, a year and a half later, in February 2014, more happy news came. The couple had welcomed their second son, Bodhi Ransom.

But in August 2015, Megan Fox filed for divorce, citing irreconcilable differences.

Brian Austin Green and Megan Fox announced they were divorcing in 2015. Image: Getty.

"They had several conflicts that led to the divorce," a source told People at the time.

"Megan worked a lot last year, and she continues to work a lot. When she is away, Brian stays with the kids. Before they filed for divorce, they had disagreements about this situation."

According to TMZ,Brian Austin Green requested spousal support from Fox due to a 2014 car accident, which triggered vertigo and made it difficult for him to work.

In April 2016, Fox then surprised the world with the announcement that she was pregnant with her third baby. She later confirmed that she had called off her divorce from Green in July 2016, as the two prepared for the arrival of their third child.

"During their separation, Brian always hoped Megan would change her mind about the divorce and he is very happy that she did," a source told People. "They both worked hard to figure out their marriage and things seem great."

In August 2016, they welcomed their third child, naming him Journey River.