Diego Costa has gone underground as he remains AWOL from Chelsea.

He has deleted his Instagram profile plunging Chelsea into the darkness regarding his whereabouts.

The Sun says the London club kept tabs on Costa's social media accounts throughout the summer after he was banished from Antonio Conte's first-team squad.

But now the Premier League champions have a job on their hands to stay in touch with the Brazilian after he chose to go incognito.

Costa, 28, is in his hometown of Lagarto in Brazil and is being fined £300,000 for every fortnight of his absence.

Chelsea and Atletico Madrid are hopeful a January deal can be done to allow the Brazil-born striker to return to Madrid, although the fee is still a big issue.