A Canadian woman was recruited by her "sugar daddy" to make a drug smuggling trip look like a holiday, she told an Australian court.
Melina Roberge, 24, refused to name the man in court, saying she feared for the safety of her family back home, Australian media reported.
Roberge is one of three Canadians who has pleaded guilty to trying to smuggle cocaine on a ship into Australia.
She and Andre Tamine, 64, initially denied involvement in the scheme.
But the pair changed their pleas regarding the import of 95kg (210lb) of drugs on cruise ship MS Sea Princess ahead of a trial that was due to start last month.
A third Canadian, Isabelle Lagace, 29, was sentenced to seven and a half years in jail in November over her part in the crime.
Australian police dogs discovered C$20m ($16m; £12m) of cocaine in their cabins after the cruise ship they were on docked in Sydney on 29 August 2016.
On Wednesday, Roberge apologised in court for her actions.
She said she made the decision to take the free vacation offered by the unnamed man without thinking through the possible consequences.
"I was meant to just be there and look like I was on holiday and look like a cover for everyone else," she said, according to 9 News Australia.
On social media, Roberge and Lagace had posted images of themselves enjoying what appeared to be a seven-week holiday on a cruise from Southampton.
According to authorities, the cocaine had an estimated street value of A$21m (£12m; $17m), making it the largest seizure of its kind on a passenger boat in Australia.
All three were charged with importing a commercial quantity of cocaine, a charge that carries a maximum sentence of life in jail.
Roberge and Tamine are both due to be sentenced at a later date.