Chelsea have completed the signing of Atalanta right-back Marco Palestra for a fee of about £47m, including add-ons.
The 21-year-old has signed a six-year deal, with the option of a further year, and becomes the first arrival since Xabi Alonso's appointment as manager.
Palestra had been the subject of an agreement to rejoin childhood club Inter Milan, but Chelsea moved quickly to surpass their £43m offer and, according to sources in Italy, offered a more substantial wage package.
"A lot of things convinced me to join Chelsea, one of the best clubs in the world," Palestra said.
"We have so many talented players here, a very strong squad and manager in Xabi.
"He has spoken to me about how he wants us to play, which is exciting, and we can't wait to compete in the Premier League."
Palestra spent last season on loan at Cagliari and was named Serie A's defender of the year.
Chelsea are now prioritising a move for a centre-back, with Crystal Palace's Maxence Lacroix expected to be their primary target, with a move for Rayo Vallecano full-back Pep Chavarria also in discussion.
Sunderland have rejected an £8m bid from Chelsea for captain Granit Xhaka, who played under Alonso at Bayer Leverkusen.
There are also agreed deals for striker Emmanuel Emegha to join from Strasbourg and winger Geovany Quenda to arrive from Sporting, while Strasbourg midfielder Valentin Barco is expected to complete a move.
The Blues are considering adding a central midfielder and a versatile forward, although much will depend on player sales after they finished 10th in the Premier League last season and failed to qualify for Europe.
Midfielder Enzo Fernandez is keen to leave and is attracting interest from Real Madrid, while Serie A side Como have held talks over a move for Trevoh Chalobah.
A number of players, including Alejandro Garnacho, Liam Delap, Wesley Fofana, Malo Gusto and Tosin Adarabioyo, also face uncertain futures.
