Shajul Islam is accused of imprisoning John Cantlie and Dutch journalist Jeroen Oerlemans against their will.
He was arrested at Heathrow airport on 9 October and appeared at Westminster Magistrates' Court on Wednesday.
Mr Cantlie, who had worked for the Sunday Times, was taken hostage by Islamist militants in Syria in July.
Earlier, a 26-year-old woman who had been arrested at Heathrow alongside Mr Islam on suspicion of terrorism was released without charge.
Speaking at the time of their arrest, Scotland Yard said the pair had flown to the UK from Egypt and confirmed both were British.
Two addresses in east London were searched under the Terrorism Act in connection with police inquiries, the Met added.
Wednesday's court hearing was told by prosecutor Piers Arnold that Mr Islam - a trainee doctor who studied at St Bart's and University London Hospital - had joined a jihadist group in Syria and worked as a medic for them.
There could be 15 British nationals in the jihad camp in Syria, he said.
The court also heard that the accused had been arrested on a flight back from Egypt with his wife and one-year-old daughter.
Mr Islam was remanded in custody. The next hearing will take place on 2 November at the Old Bailey.
A 26-year-old man charged with the kidnap of a British photographer in Syria has been remanded in custody after appearing in court.