Andre Schuerrle described his "honour" to sign for Chelsea, after the club officially announced his signing on Tuesday.
The Premier League side confirmed a deal had been reached with Bayer Leverkusen a fortnight ago, and have now revealed the forward has put pen to paper on a five-year contract.
And the Germany international is itching to get started for Jose Mourinho's side.
"I am so happy now I have signed and it is an honour for me to play for this club, with this team and for these great fans," Schurrle told the club's official website.
"I am really looking forward to it."
After a third-place finish in the Premier League last season, Schuerrle is confident the club can battle for the top honours next year.
He added: "I think we have a great team with some very talented young players. We can all improve ourselves, and under Jose Mourinho I'm confident we can have a really great season.
"For this club, winning titles is always the main objective. We are capable of doing well in the Premier League, Champions League and the cup competitions as well, and I hope to play a big part.
"It was my dream to train every day with such talented players so I'm very much looking forward to it."
On playing for Mourinho he added: "I'm really looking forward to working with him. I got to know him at Michael Ballack's testimonial a few weeks ago where we talked a little bit.
"He gave me advice on where to live and also explained what he expects from me.
"He's a very good person with a big personality; he's a great manager so it's an absolute honour for me to now be one of his players."
The 22-year-old moved to Mainz in 2009, and was a key part of the side that achieved a UEFA Europa League spot in the Bundesliga at the end of the 2011 season.
His form earned him a move to Leverkusen where he has continued to earn plaudits, as he helped the team clinch a third-place finish in the Bundesliga in the last campaign, and automatic UEFA Champions League qualification.
Schuerrle, who has notched seven goals in 24 appearances for Germany, will wear the number 14 shirt for his new side.