Khan, chief of the Pakistan Tehreek-e-Insaf (PTI) party, has challenged his arrest in a corruption case in the high court.
The PTI says Khan will make a public statement outside the court after the hearing and has urged his followers to reach Islamabad, Al Jazeera reported.
Khan is due to appear in court after the Supreme Court ruled his arrest earlier this week “unlawful”.
The dramatic arrest on Tuesday triggered clashes with police and paramilitary forces across the country, killing nearly a dozen people. The army was called in to restore order.
Police in capital Islamabad have imposed an emergency order banning gathering of more than four people as Khan’s supporters are expected to march to the capital.
Former Federal Minister for Human Rights and a close aide of Khan Shireen Mazari has been “illegally abducted”, according her party Pakistan Tehreek-e-Insaaf (PTI).
Another prominent leader and former Punjab health minister Yasmin Rashid was also arrested, the PTI said.
The Pakistani government has vowed to re-arrest Khan should he be released by the Islamabad High Court.