Dutch international Nathan Ake became Premier League side Bournemouth's record signing on Friday as they paid a reported £20 million ($26m, 22.8m euros) to champions Chelsea for his services.
The 22-year-old central defender -- who is Bournemouth's third signing of the close season following those of Bosnian international goalkeeper Asmir Begovic and veteran England striker Jermain Defoe -- shone for the "Cherries" when on loan from Chelsea last season.
Ake, who notably scored the winner for Bournemouth in a remarkable come from behind 4-3 win over Liverpool before returning to Chelsea in January, said he could progress more as a player at his new club as playing opportunities at the champions were scarce.
"I had a great time here last season so I'm really happy to be back," Ake told the club website.
"It's an exciting challenge. Chelsea is a great club and I learned so much there but this is a new step and the right place for me to develop even more.
"The fans haven't seen the best of me yet. I always set the bar high so I know there is a lot of things I still have to work on.
"With the help of the manager here I know I can keep improving and become a better player."
Bournemouth manager Eddie Howe, who finalised Defoe's move on a free transfer on Thursday, said he was delighted to have persuaded the two-times capped Ake to join the club on a permanent basis.
"I am delighted that we have completed the signing of Nathan on a permanent basis," said Howe.
"He is someone we know all about, having had a very successful loan spell here last season.
"Nathan is an outstanding young player with a fantastic attitude and a great desire to learn and develop.
"He has a very bright future ahead of him and I'm very pleased to say that future is here."