On Friday, Manchester City announced re-signing Ilkay Gundogan on a free transfer after his Barcelona exit.
Gundogan made his return to the Citizens after spending a year in the Camp Nou.
The former Germany's international can make his first appearance after the return on Saturday's Premier League game against Ipswich at the Etihad Stadium.
The midfielder's contract is a one-year contract with an option for a further year.
Pep Guardiola responded to the news, saying: "When managers say 'this is the transfer window, anything can happen', this is the real proof."
He added: "It was a complete surprise, unexpected. We didn't have any doubts when the possibility was open. Absolutely delighted he's back."
Gundogan, who spend seven years with the Citizens before moving to Barcelona last year, was the first signing for the team under the reign of Guardiola seven years ago.
Now, he could be the last signing of Guardiola whose future is not certain with the Citizens after the end of the newly-kicked off season.