Police arrested David Chatwood, 57, at the home he shares with The Only Way is Essex stars and their mum, in Brentwood, Essex.
Chatwood, who has been with the reality TV stars’ mum Sue Wells, 42, for several years, is accused of international conspiracy to steal and transfer criminal property, along with five other men.
A source said: “They are close to Dave. He is the man they see as their real dad.”
Billie, 21, and Sam, 20, are still recovering after they were both brutally attacked by a girl gang last week.
This morning, Sam tweeted: “Just when u think things can’t get worse !! 🙁 …. ‘be strong’ x x”
The theft Chatwood, also known as Chatty, is accused of happened in Antwerp, Belgium, on October 19 while a lorry was taking the gold bars to the UK.
The Metropolitan Police’s Special Projects Team began an investigation with Belgian Police.
Detective Inspector Sarah Staff said: “International liaison has resulted in a successful operation which has seen a significant amount of this property recovered.”
Chatwood and the other five men appeared at Barking Magistrates’ Court and were remanded in custody until January.
A TOWIE spokesman declined to comment on the arrest. Earlier this year, the girls’ real father Lee was given a community service order and told to attend a domestic violence programme after he was convicted of assaulting his partner Fay Simmons in June.