Schapelle Corby admitted her guilt and said the fateful 2004 drug run that saw her locked up for ten years was actually her fourth trip to Bali as a courier, according to fellow Australian prisoner Renae Lawrence.
Lawrence, one of the Bali Nine heroin couriers, has also alleged in an interview broadcast on the Ten Network that Corby faked mental illness to get a shorter sentence - a tactic that worked.
Corby was granted a five-year sentence reduction in 2012 by Indonesian President Susilo Bambang Yudhoyono who cited compassionate grounds because of the Australian's mental illness. This is likely to be the most damaging revelation from the interview.
A spokesman for the Indonesian Justice and Human Rights Minister Amir Syamsuddin said of that allegation: "That is her [Corby's] good luck".
However, if the Indonesian media pick up the line and use it to criticise Dr Yudhoyono for being too cosy with Australia, it may affect Corby's parole.
As it stands, the minister is still considering whether to send her back to Kerobokan prison over sister Mercedes' interview last month with Channel Seven's Mike Willesee.
But the allegation about previous drug runs would change nothing, said two Indonesian government spokesmen. Corby had been convicted and served the bulk of her sentence and there was no evidence of other trips, they said.
In the interview, Lawrence said in the five years she lived in the same cell block as Corby, she "did a good job on keeping secrets but she let one slip one night" to Lawrence and another prisoner.
"She said that she knew the marijuana was in the body [sic] bag but that the person who was supposed to be at the airport at that time didn't show up for work or couldn't be there for some strange reason, I don't know ... And that's how she got caught.
"She told me and the other prisoner that she done it more than this time. She got away with it before ... and she said how she had to keep saying that she wasn't guilty because if she changed her mind she was scared she would lose all the Australian support."
Elaborating on the earlier drug trips, Lawrence said: "She said she brought the drugs before, three times. The first time she didn't know [about the drugs] until she got through the airport, but the other times she knew."
Visa stamps in Corby's passport show she made four visits to Bali in the years before her 2004 arrest: in March, August and December 1999, and in July 2000.
Corby, who has also repeatedly denied she smoked cannabis, had "used since she was a teenager," according to Lawrence.
On the question of Corby's mental illness, Lawrence said, "She, um, actually, she acted crazy ... She said it herself. She played crazy so that she would get more sympathy and more time off from the President of Indonesia. Which actually worked for her ... She would put on more of an act when someone important came into the block like the doctor of the jail boss."
When Dr Yudhoyono granted Corby five years off her sentence (reducing it from 20 years to 15) in 2012, he cited her mental illness as the main reason.
Prison sources have in the past blamed Lawrence, who was responsible at one point for administering anti-psychotic medication to Corby, for getting the dosage wrong and prompting her mental illness.
Lawrence, who had a sometimes antagonistic relationship with Corby, appears to be motivated partly by anger to give the interview.
Lawrence intends to apply for parole next year, but like other members of the Bali Nine was infuriated by the Corby family's inept handling of Schapelle's release.
This included initially living in a five-star luxury villa, arranging a lucrative paid interview with Willesee (which fell through over objections from the Indonesian government) and implying that Schapelle Corby may have been set up by Indonesian authorities.
Lawrence said these events may damage the chances of others.
"I don't know why she has to keep carrying on like she is. She's not helping herself and she is not helping us other foreigners who want to go for parole ... she should just be quiet ... If she keeps doing what she's doing she is going to ruin it for everyone."
The revelations in the paid interview will infuriate the Corby family and supporters who continue to insist on Schapelle's innocence.
The Corby family released a media statement ahead of the interview saying Schapelle Corby denied admitting her guilt to Lawrence.
"The claims by Renae Lawrence that Schapelle confessed to her that she had knowingly smuggled the marijuana in her boogie board bag are false," the statement said.
"The further claims by Renae Lawrence that Schapelle had done so on many occasions are preposterous, maliciously false and a creation of her own fantasy."
Corby was convicted in 2004 of couriering 4.2 kilograms of cannabis to Indonesia and sentenced to 20 years in jail, which was later reduced to 15 years.
- Sydney Morning Herald