Ant Anstead has come out fighting against his ex-wife.

On Thursday, the Celebrity IOU Joyride host filed for full custody of the two-year-old son, Hudson London, that he shares with Christina Haack.

The England native and the former Flip or Flop co-host got married in December 2019... welcomed their son in September 2019... and broke up about a year later.

"We are grateful for each other and as always, our children will remain our priority," Christina said in September 2020.

Since that time, Anstead got into a serious relationship with Renée Zellweger; while Christina actually got married (for the third time) to Joshua Hall three weeks ago.

In documents obtained by TMZ, Anstead lays into Christinas as a parent, alleging she has scarcely spent any time with their child.

According to Anstead, Christina has spent an average of "9 full days each month" with Hudson over the last 20 months.

He also accuses his ex of exploiting the toddler, sharing his photo on social media at all times in order to build her following -- even using the kid at times in paid/sponsored posts that earn Christina money.

Christina -- who also shares son Brayden James, 6, and daughter Taylor Reese, 11, with ex-husband Tarek El Moussa -- responded to Anstead's filing and Anstead's allegations as follows:

“What Ant is doing deeply saddens me.

"If this was really about Hudson, as he says, this should have been handled privately with a private judge or mediation, as myself and my attorney have suggested.

"I have had my share of ups and downs but I am a good mom and I love my children with all my heart and I will always protect them.”

Ant, however, isn't backing down.

He included at least one example of his ex-wife's allegedly irresponsible parenting in the court papers.

Earlier this month, he said, after spending time with Christina, Hudson came back with a terrible sunburn that was so bad it left him crying in pain.

Anstead claims that he texted Christina about it and she replied: "It didn't feel hot. Give him some Tylenol im sure it will be better tomorrow."

Ant explains that the exes have shared custody at the moment.

Howeve, he's now asking for full custody -- with Christina getting alternating weekends ... and he also wants a judge to prevent the HGTV personality from posting Hudson in any "commercial endeavor" unless he agrees to it.

On her Instagram page, meanwhile, Christina appears to have fired back at her ex-husband.

She shared a meme on her account that reads as follows:

She will test you and see what you're made of, just by being herself, because the nature of a strong woman will identity who a man really is. if he feels threatened or has the need to possessively control her, it will be revealed.

and the funny thing is that she doesn't want to call the shot.

she wants a man who will embrace her strength and stand by herr side. a man who will walk who her but will lead with taking the first step.