Thiago persuaded by Pep talk
The Spain Under-21 captain has signed a four-year contract with last season's Bundesliga, DFB-Pokal and Champions League treble winners and he said he cannot wait to work with his new team-mates, and in particular Bayern's new coach.
"I played under him in the (Barcelona) youth team and I've got him to thank for everything that I have achieved so far," he said in Munich.
"I never had a coach like him. He's unique.
"After the European Under-21 Championship, I spoke with Guardiola on the phone and, after that, I decided to come to Bayern.
"I discussed last season and the upcoming season with the club. I wanted a new challenge."
Thiago joins Mario Gotze as one of two new faces expected to strengthen a Bayern side which won everything last season.
"I think it's fantastic," said Bayern's chairman Karl-Heinz Rummenigge at the player's official presentation.
"The coach now has a big squad to choose from and there is of course a big competition for places.
"We didn't buy him because he knows the Barcelona way, but because he's a gifted footballer."
He has already demonstrated that for both for club and country, scoring a hat-trick in Spain's European Under-21 Championship final victory over Italy earlier this summer, having established himself as a regular in the Blaugrana side before reaching the age of 21.
He is now ready for the next step in his career with Bayern - the only club he could have imagined joining after Barca.
"It's a special city with a particular flair," he said. "There's a real passion for football in the city.
"There are few teams as strong as Bayern and Barcelona. This is a fantastic side. I don't want to mention any names in particular, I'm just looking forward to playing with every single one of them."
His first appearance for Bayern could well come against the Catalans next Wednesday in a mouth-watering pre-season friendly at the Allianz Arena.
"I'm fit and ready," said Thiago. "Barcelona have some exceptional players and they've all wished me lots of luck and all the best, but I'm ready to face my former team-mates."