One of those quick to offer congratulations was the PM himself.
Nothing wrong with that you might think.
Well, if the responses are enough to go by, not even the biggest football fairytale of all time is enough to warrant a positive response to David Cameron.
Obviously, a lot of the fire was directed at the now infamous occasion where the PM forgot which team he supported.
Others simply questioned the sincerity of the tweet.
Or if he even sent it himself...
On the whole, the well-meaning tweet seemed rather unwelcome...
At least there was some career advice though...
Mostly though, it was just a lot of weirdness...
The remarkable outcome to the season has bee a true football fairytale.
They lost just three games in what has been described as "the most unlikely triumph in the history of team sport".
Former Leicester player, Gary Lineker said: "I can't think of anything that surpasses it in sporting history. It is difficult to put over in words.
"I got emotional. It was hard to breathe. I was a season ticket holder from the age of seven. This is actually impossible."
Leicester still have a game to play against Everton on Saturday.
Suggested For You
SUBSCRIBE AND FOLLOW
Get top stories and blog posts emailed to me each day. Newsletters may offer personalized content or advertisements.Learn more