Julian Assange, the founder of Wikileaks, will marry his long-term partner Stella Moris on Wednesday inside a high-security prison in southeast London in a small ceremony attended by four guests, two official witnesses, and two security guards.

Assange is wanted by US authorities on 18 counts related to the release of vast troves of confidential US military records and diplomatic cables by Wikileaks.

The 50-year-old, who denies any wrongdoing, has been imprisoned at Belmarsh since 2019 and was previously imprisoned at the Ecuadorean embassy in London for seven years.

He fathered two children while living at the embassy with Moris, a lawyer more than a decade his junior whom he met in 2011 when she began working on his legal team. Their romance began in 2015.

The registrar-led ceremony will take place during visiting hours at the prison, which has housed some of the most notorious criminals in Britain, including child murderer Ian Huntley.

Vivienne Westwood, a British fashion designer who has previously campaigned against Assange’s extradition, designed Moris’ wedding gown and Assange’s kilt, a nod to his family ties to Scotland.

This month, Assange was denied permission to appeal to the Supreme Court of the United Kingdom against a decision to extradite him to the United States. He could still file a legal challenge to the government’s decision to approve his extradition.