Andrew Tate and his brother Tristan will stay in custody until 27 February after a Romanian court extended their police detention.
The pair are being investigated over allegations of sexual assault and exploitation.
A judge has decided they must remain in prison for a further 30 days while police investigate.
The self-proclaimed misogynist was arrested in Bucharest on 29 December on charges of being part of an organised crime group, human trafficking and rape.
His brother Tristan and two Romanian women were also taken into custody. All deny the charges.
Last week authorities in Romania seized several luxury cars from his villa on the outskirts of the capital.
The 36-year-old British-US citizen has 4.4 million followers on Twitter and was previously banned from various prominent social media platforms for expressing misogynistic views and hate speech.
Prosecutors have said the Tate brothers recruited their victims by seducing them and falsely claiming to want a relationship.
The former Big Brother contestant and kickboxer is believed to have lived in Romania since 2017.
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Ramona Bolla, a spokesperson from Romania’s anti-organized crime agency, DIICOT, said that prosecutors requested the second 30-day extension on Thursday to keep all four in detention while investigations continue.
That request was granted on Friday, Bolla said.
The judge’s decision came after Tate, his brother and the two Romanian women lost an appeal last week at a Bucharest court, which ruled to uphold a judge’s 30 December move to uphold an earlier decision to extend their arrest from 24 hours to 30 days.