Lionel Patea has pleaded guilty to murdering Kiwi-born woman Tara Brown.
Patea was set to go on trial today in Brisbane for the murder of Brown, his ex-partner.
About 40 of Brown's family and friends were in the courtroom this morning to hear Patea's last-minute plea change.
Brown's mother is sitting in the front row of the public gallery.
The court has just heard that Patea cannot remember murdering his ex-partner.
His lawyer has revealed that in the days leading up to the brutal attack Patea was "self medicating" with illicit substances.
He remembered some parts of chasing Brown around the Gold Coast in his car - but not the crucial moments.
"He has no recollection of the incident," his lawyer told the court.
"He recalls part of the incident at the intersection but he can't recall the incident itself."
Patea has written a letter to the court which has been handed to Justice Mullins.
The court earlier heard details of Brown and Patea's relationship.
It has been revealed that Brown had left Patea after an altercation at Auckland International Airport as the pair were waiting to fly back to the Gold Coast after a trip home.
She spent time in a safe house and was "trying to get her life back together" and find a new home for herself and her young daughter.
The day she was killed she dropped the little girl at daycare.
Little did she know Patea had earlier called the daycare centre to confirm that his child would be attending that day.
When Brown left the centre Patea followed her, chasing her at speeds of up to 200km/h before ramming her car off the road.
As Brown fled Patea she managed to call 000 - Australia's emergency services line.
The court heard this morning that the 24-year-old could be "heard screaming for help".
"She was screaming that he is going to stab her," the prosecutor said.
Brown repeatedly yelled to the 000 operator where she was driving.
"Sounds of a crash can then be heard ... a short time later she can be heard in a very sub almost moaning tone saying 'help me, help me, help me'," said the prosecutor, explaining the call.
The 000 operator tried to get Brown to speak to her, but there was no response.
"Lionel stop ... Please help me," Brown was heard to day.
Sixteen "thumping sounds" could then be heard on the 000 call.
Then, another female shouting "what the f*** are you doing?".
Patea responded with "she's got my kid", then a further 13 thumping noises.
And then, silence.