The former health secretary said he was entering the ITV programme’s jungle to “go to where the people are – not to sit in ivory towers in Westminster”.
The MP, who has had the Tory whip suspended by chief whip Simon Hart, insisted “I haven’t lost my marbles” by deciding to join the reality show after being suspended from the parliamentary Conservative Party.
The West Suffolk MP insisted his “first priority” is to his constituents as he flew more than 10,000 miles to join the ITV show, which starts on Sunday – and insisted that he had not been swayed by the cheque on offer, which he will be donating to charity.
A casually dressed Mr Hancock was spotted arriving in Brisbane as he prepared to enter the jungle.
Mr Hancock defended his decision in an article for The Sun, arguing it is “a great opportunity to talk directly to people who aren’t always interested in politics”.
He said reality TV is an “honest and unfiltered” way to communicate with voters.
“It’s our job as politicians to go to where the people are – not to sit in ivory towers in Westminster,” Mr Hancock wrote.
“There are many ways to do the job of being an MP. Whether I’m in camp for one day or three weeks, there are very few places people will be able to see a politician as they really are.”
He added: “So, the truth is, I haven’t lost my marbles or had one too many pina coladas. It’s something I’ve given a lot of thought to.”
Mr Hancock said he wants to use the “incredible platform” to raise awareness of dyslexia and insisted it “wasn’t the cheque” that made him decide to join the show.
He said he turned down the programme “twice this summer” but had a “change of heart” after workers asked a third time last week.
The MP said it was not the money that changed his mind, saying he will make “a donation” to St Nicholas Hospice Care in Suffolk, though he does not say he will give up the full amount.
He said he feels able to go to the jungle now the “Government is stable”.
Mr Hancock said he can be reached on “any urgent constituency matters”.
But Cabinet minister Mark Harper said Mr Hancock had not made the “right judgment” and would now have to decide whether he wants to continue as an MP on his return.
Transport Secretary Mr Harper told Sky News: “The chief whip has made the position clear, which is he’s made a decision that going on I’m A Celebrity is not compatible with doing your job properly as a Member of Parliament.”
Pressed on whether Mr Hancock should stand down as an MP, Mr Harper said: “What he chooses to do in the future is a matter for him.”
Mr Harper told LBC: “I think we can draw conclusions from the fact that the whip has been taken away that perhaps Mr Hancock hasn’t made the right judgment in this case.”
Meanwhile, Mr Hancock is facing questions over whether he broke rules on seeking permission over jobs taken within two years of leaving office.
Mr Hancock did not seek advice from the Advisory Committee on Business Appointments (Acoba) before agreeing to the appearance, the PA news agency understands.
Lord Pickles, the Conservative chairman of the anti-corruption watchdog, which advises on post-ministerial jobs, is expected to write to Mr Hancock to demand clarification.
Under the rules, Mr Hancock should seek clearance from Acoba for any new employment or appointments he takes on until next June.
A spokesman for Mr Hancock said the guidance “was followed in good faith”, adding: “The Acoba website clearly states that it does not regard media appearances as an appointment or employment.”
However, the website only says that “one-off” activities are not applicable, with any “longer-term arrangement” requiring a request to Acoba.
Depending on how he fairs during public votes, Mr Hancock could remain in the jungle for weeks.
In April, Tory MP and former housing minister Esther McVey was found to have broken the rules for failing to seek Acoba’s advice over her “regular engagement” as a GB News presenter.
Mr Hancock can continue to pick up his taxpayer-funded salary as an MP while he is in the jungle.
But Liberal Democrat Treasury spokeswoman Sarah Olney said: “The taxpayer should not pay him while he refuses to do his job.”