Former striker Gary Lineker believes Leicester achieved the impossible after the Foxes were crowned Barclays Premier League champions.
Lineker will now have to present an episode of Match of the Day next season in his underpants following a pledge made on Twitter after the Foxes' 2-1 win over Chelsea in December.
Lineker told Radio 5 Live: '' 'I just think it's generally the biggest sporting shock. I can't think of anything that surpasses it. When it's your own team it's too extraordinary. Too difficult to put over in words.
''To be honest I got a bit emotional at the end of the game. I just couldn't hold it back. It was quite hard to breathe the last few minutes to be honest.
''I've followed them since I was a little kid... I saw them in a cup final - lose - that was the closest we ever got to big glory. Won the league cup a couple of times but this is just something else. This is actually impossible.
''There were no odds that I would have taken at the start of the season. No odds. You could have given me 10 million to one and I'd have said 'Nah, it's a waste of a quid'.
''It's extraordinary. I'm from there and I went to play for them for a couple of years. I even kind of part owned them for a while when they were in trouble.
"To see where they are now and to enjoy this moment especially with my family, it's incredible.''
Mark Selby was winning his second world snooker title at the time, but a big Leicester fan, he had double cause to celebrate afterwards.
''I can't believe it - I don't know what's more of a shock, me winning the title twice or Leicester becoming the champions. Hopefully in another two years I'll come back and win it again and Leicester will be Premier League champions again.''
Leicester mayor and lifelong fan Sir Peter Soulsby said: '' 'The first thing now is we can book the open top bus. I have deliberately not been doing any announcements in how we are going to celebrate until it was confirmed but the preparations will begin for the celebrations which will take place immediately after the end of the season.''
On whether manager Claudio Ranieri would get the freedom of Leicester, he added: ''I bet there will be a lot of people asking for it. It's too early to say how we're going to do it but I'm sure we'll want to recognise what's been an amazing achievement for Claudio and an amazing team.''
Chelsea captain John Terry, who played under Ranieri at Stamford Bridge, wrote on Instagram: ''Congratulations to Claudio Ranieri and Leicester City. A real gentleman and a top manager.''
Another former Fox Robbie Savage believes the title is the ''greatest achievement in sporting history''.
Savage said: ''It's going to be one unbelievable night for Leicester. Those fans have been with that team through thick and thin.
''The greatest achievement in sporting history. I don't think anything betters this. It's incredible.
''They've proved a lot of people wrong. I was a massive skeptic of Claudio Ranieri. I didn't think they could win it but they've proved me and a lot of people wrong and they thoroughly, thoroughly deserve it. What an amazing night.''
Former Liverpool defender and Sky Sports pundit Jamie Carragher added on Sky Sports 1: ''I think there's no doubt that is the greatest achievement in the history of our game, I think it's unprecedented.
''I think in the past there have been teams who have come up and won the league but it was more of a level playing field then. Now, what Leicester have done is give inspiration to every football club, every manager, player, supporter all across the land that one day that could be them.
''Football had become a closed shop with the same teams winning year after year and you never believed a story like this could happen, but it has and you just think what that could do for the rest of football now and if it could change and you could see more of this more often.
''But it's a fantastic achievement and you can't quite believe it's happened. Statue for Ranieri in the morning I think, isn't it?'
Former Tottenham manager Harry Redknapp believes Leicester have the means to keep hold of their star players.
He told talkSPORT: "They've got very wealthy owners there, I'm sure they'll strengthen and they'll make sure that people there are looked after and they'll keep the players. It'll be interesting to see next year again."
Sir Peter Soulsby, the Mayor of Leicester, said there had already been plenty of suggestions about how the city can pay tribute to Ranieri.
He also recognised the role played by former Foxes boss Nigel Pearson in the club's success.
Soulsby told Sky Sports News: "S treet names after him (Ranieri), freedom of the city, statues...I don't know what it will be. I do know we've got quite a lot of partying ahead of us as a city to the end of the season. And then a big celebration.
"Very proud of our team. We've been amazed by the performance of the team on the pitch. The inspiration given by two managers, Nigel Pearson first and now Ranieri. They really are something that the city has got behind, and are very very proud of."
Former Germany and Arsenal goalkeeper Jens Lehmann, meanwhile, believes Leicester centre-back Robert Huth should be named in Germany's squad for Euro 2016.
The last of Huth's 19 caps for Germany came in 2009, but Lehmann wrote on Twitter: " Congratulations to Leicester City and Robert Huth. You deserve to play for your country again in France!"