Chelsea have completed the signing of former midfielder Nemanja Vidic for a fee in the region of £20m, Sky Sports understands.

The 25 year old originally moved away from Stamford Bridge in 2011 as part of the deal that saw David Luiz arrive from Benfica.

He has returned on a five and a half year deal, and becomes the Blues first signing of the January transfer window.

During his first spell at the club, the Serbian international made just three substitute appearances before moving to Portugal.

He could make his second Chelsea debut in Sunday afternoon’s clash with Manchester United.

Meanwhile, the club have been boosted in their hopes of signing Southampton left-back Luke Shaw following the news that chairman Nicola Cortese has left the club, according to the Express.

The 18 year old has been linked with a move to a number of clubs though both Cortese and manager Mauricio Pochettino have dismissed any speculation that they will sell.

However, with rumours that the Saints boss will follow his former boss out of the door at St Mary’s, the Blues are waiting to pounce.

Finally, midfielder Nathaniel Chalobah has returned to the club following his loan spell with Nottingham Forest.

The England U21 international made twelve appearances for the East Midlands side, scoring twice.