It was announced on Tuesday evening that Jack had "withdrawn" from the ITV series, after just two days.
A spokesperson for Jack said in a statement: "In the last few days Jack has been the subject of a succession of media stories which, given his position as a contestant on 'I’m a Celebrity Get Me Out Of Here' - filmed in the Australian jungle, with no contact with the outside world, he has been unable to respond to.
"Since it is only fair that everyone should be aware of any allegations made against them and should also have the right to defend themselves, it was agreed that it would be better to bring him out of the show. Jack agrees with this decision which was made by his representatives and ITV and thanks everyone who has supported him in the show this far."
Tonight Jack spoke out in a YouTube video posted to his 1 million plus subscribers.
He tweeted: "You all deserve answers as to what's been going on in the press recently, I have filmed a video to apologise for what I've said in the past and to thank you all for the incredible support."
In the video, Jack tells fans: "To be honest I just want to start off with that I'm sorry, I'm just really, really sorry.
"I'm sure most of you have seen that a lot of stuff have been written in the press over the last few days.
"I thought the least you deserved was for me to come home and just sit down and talk to you and explain everything that has been going on.
"I'm so sorry to anyone that I offended, anyone I upset, anyone I made feel uncomfortable."
Responding to tabloid stories, Jack said: "I was young, I was stupid, I was careless.
"I just wasn't thinking back when I'd just left school and I didn't know what I was doing getting into arguments with people on Twitter before I knew I'd have any impact online."
He added: "Growing up online is hard, all I can do is beg and encourage that you guys don't make the same mistake as well.
"Don't ever put anything online that you wouldn't say to your mum."
And Jack concluded: "I'm just so embarrassed, we've had such an amazing year.
"One of the reasons I went on the show was because I saw it as a huge achievement to see off the year and I feel like I completely messed it up."
I'm A Celebrity continues nightly on ITV at 9PM without Jack.