The Bayern Munich boss has been a long-term target for City, but he opted for a year's sabbatical from coaching before taking up the job in Germany, as reported by the Daily Mail.
The move has sent a shiver down the spines of rival clubs who now face the daunting task of stopping the world's richest team with arguably one of the planet's best managers at the helm.
'I am absolutely certain he will win trophies'
And now pundit and Premier League legend Shearer, who scored 313 goals in 622 career games for club and country, has told his latest blog on Coral the club is effectively guaranteed trophies in the coming years.
"There is no doubt that Guardiola will bring some charisma to the Premier League," Shearer wrote on Coral.
"He wins trophies and I am absolutely certainly he will win trophies at Manchester City.
"He’ll be given a massive budget to bring is some players in the summer... he will without doubt attract some of the big players in the world.
"Manchester City have the funds to be able to offer the top wages so put all of those pieces together, City are going to be some force going forward.
"There are no guarantees in football but he is probably as close as you can get to guaranteeing trophies for your club."
Shearer's City timeline
Shearer has been particularly outspoken about City this season.
Last month the former Newcastle United and Blackburn Rovers striker said he had serious doubts over City's mentality to cope in a title race.
He then claimed Yaya Toure could be the club's downfall in the fight for the title a week later.
But Shearer went on to make a massive U-turn after City's 4-0 drubbing of Crystal Palace two weeks ago when he said they were perfectly poised to win the league.
Ominous for rivals
His latest views will be music to a true Blue's ears, though, and he could well be right.
Whether Guardiola will have the pulling power to lure any of his former players from Barcelona and Bayern away from such massive clubs remains to be seen.
But it will certainly be fascinating to see the Spaniard and his footballing philosophy in action in the Premier League.
It is ominous for the likes of City's bitter rivals United and the rest of the top flight's established elite too if they are to compete with the Citizens long term.