Brian Earl Johnston, 37, on Wednesday was called as a witness during the Brisbane Supreme Court trial of Bradley Bell, who has pleaded not guilty to murder.
The 29-year-old is accused of having aided Johnston to kill Ms Wilkinson, 27, through his decision to drive him to his estranged wife's Gold Coast home after buying a 20-litre can of petrol together.
Pink burn scars were visible on the back and side of Johnston's bald head as he took the stand while wearing a black suit.
The jury heard Johnston was seriously injured early on the morning of April 20, 2021 when he set Ms Wilkinson on fire after stabbing her multiple times.
Johnston told the court during his brief time giving evidence on Wednesday he did not "really remember the details" of how he killed Ms Wilkinson but accepted he caused those injuries.
Defence barrister Edwin Whitton asked Johnston if he told Bell about his intent to kill Ms Wilkinson before he did so.
"No, sir," Johnston said.
Johnston agreed he had told Bell, while working together as marine engineers, that he wanted to take his own life and did not plan to be at work on April 21, 2021.
Mr Whitton told the jury Bell would testify in his own defence that he had lied to police during an 80-minute interview on July 20, 2021 as he wanted to help them investigate Johnston.
"The most important thing he will tell you is ... he accepts he lied to the police. He lied when he said he knew Brian Johnston intended to kill Kelly Wilkinson," Mr Whitton said.
"He lied because he realised he had become involved in something terrible and he was scared."
Bell told the jury he had smoked cannabis before he took part in the interview and it had affected his thinking.
"I was not in any headspace to do a police interview," he said.
Mr Whitton asked Bell if he was aware of his rights to silence or legal representation during the interview, which he did not use.
"Yes. Getting a lawyer would be a sign of guilt. I hadn't done anything wrong," Bell said.
He said he had no idea Johnston had tried to "tie up and burn" Ms Wilkinson until an undercover police officer told him about it.
When asked why he later said during the interview he knew Johnston wanted to tie up and burn Ms Wilkinson, Bell said "it fit the story" he wanted to give police.
Under cross-examination from crown prosecutor David Nardone, Bell admitted having lied to police multiple times but denied being "a liar".
Bell denied he thought about why Johnston asked for a lift to his estranged wife's house at 3am.
"I was stoned, I was tired. I wasn't functioning," Bell said.
The trial continues before Justice Michael Copley.
Lifeline 13 11 14
beyondblue 1300 22 4636
1800 RESPECT (1800 737 732)
10°C