The Australian radio hosts at the centre of the royal hospital hoax say they are "gutted and heartbroken" over the death of nurse Jacintha Saldanha.
Mrs Saldanha was found dead on Friday, three days after taking the hoax call.
Mel Greig and Michael Christian wept as they said "not a minute goes by where we don't think about her family".
They had pretended to be members of the Royal Family asking about the Duchess of Cambridge, who was being treated in hospital for acute morning sickness.
Mrs Saldanha's post-mortem examination is due to take place on Tuesday, the Metropolitan Police have said.
The prime minister has described her death as "completely shocking". David Cameron told journalists: "I feel incredibly sorry for her and her family."
In an interview for Channel Nine's A Current Affair programme, Mr Christian told presenter Tracy Grimshaw: "When we thought about making a call it was going to go for 30 seconds, we were going to be hung up on, and that was it. As innocent as that."
Ms Greig said: "We thought 100 people before us would've tried it. We thought it was such a silly idea and the accents were terrible and not for a second did we expect to speak to Kate - let alone have a conversation with anyone at the hospital. We wanted to be hung up on.''
The pair said they had heard about Mrs Saldanha's death in the early hours of Saturday morning.
"It was the worst phone call I've ever had in my life,'' said Ms Greig.
Asked what his immediate reaction had been, Mr Christian wept and said: "Shattered, gutted, heartbroken and obviously you know. Our deepest sympathies are with the family and the friends.
"Prank calls are made every day, on every radio station in every country around the world, and they have been for a long time and no-one could've imagined this to happen.''
Ms Greig said they had expected to be hung up on and she said: "The accents were terrible. You know it was designed to be stupid. We were never meant to get that far from the little corgis barking in the background - we obviously wanted it to be a joke.
"If we played any involvement in her death then we're very sorry for that. And time will only tell."
Asked about whether she felt there was a "witch hunt" against them, Ms Greig said: "There's nothing that can make me feel worse than what I feel right now. And for what I feel for the family. We're so sorry that this has happened to them."
The Duchess of Cambridge was taken to King Edward VII Hospital in central London last Monday, suffering from an extreme form of morning sickness called hyperemesis gravidarum.
Mrs Saldanha had answered the presenters' call and, believing they were members of the Royal Family, put them through to another nurse, who described the Duchess of Cambridge's condition in detail.
Mrs Saldanha was pronounced dead on Friday morning at staff accommodation close to the hospital. An inquest into her apparent suicide is due to be opened in the next few days.
Labour MP Keith Vaz, who has visited Mrs Saldanha's husband Benedict Barboza and family at their home in Bristol, said: "They will love her and cherish her and take her to India for burial."
He said Mrs Saldanha's family were Mangalorean Catholics - originating from the city of Mangalore in India - and he said they were a "small, strong family".
The family of Mrs Saldanha said in a statement that "we as a family are deeply saddened by the loss of our beloved Jacintha".
Mr Barboza had a meeting with Mr Vaz at the House of Commons on Monday. Afterwards, the MP described Mrs Saldanha as a "loving mother and a loving wife" and said the family "miss her every moment of every day".
King Edward VII's Hospital said it "has at all times offered to provide whatever assistance and support it can to Mrs Saldanha's family".
Her family made a private visit to the hospital on Monday, which has now set up the Jacintha Saldanha Memorial Fund. This will offer financial support to Mr Barboza and her children.
And the hospital also said it would hold a memorial service for Mrs Saldanha later this week.
Earlier the presenters' employer, Sydney radio station 2DayFM, said at least five attempts had been made to obtain the permission of the two nurses involved before airing the call.
The radio station said it was going to review its broadcasting practices.
But the King Edward VII Hospital said that the radio station "did not speak to anyone in hospital senior management, or anyone at the company that handles our media enquiries" following the hoax call.
The Australian press has reported that the Hot 30 radio show, on which the two DJs broadcast the call, has been cancelled.
In an interview with a Melbourne radio station 3AW, Rhys Holleran - whose company Southern Cross Austereo owns 2DayFM - said his staff had tried several times to make contact with Mrs Saldanha and another nurse at the King Edward VII's Hospital to get their permission to use the prank conversation before it was transmitted.
Mr Holleran said the death of Mrs Saldanha was "tragic" and "regrettable", but that it "could not have been foreseen".
Some legal experts in Australia have said if the radio station did not tell the nurses they were being recorded, or received their permission to broadcast the conversation, they may be in breach of a number of laws.