Shamima Begum set to begin her legal challenge over the removal of her British citizenship
Ms Begum, now 20, left the UK in 2015 and was found in a Syrian refugee camp in February after living under IS rule for more than three years.
Former home secretary Sajid Javid revoked the teenager's citizenship later that month, prompting her family to take legal action against the Home Office in a bid to overturn the decision.
On Tuesday, the Special Immigration Appeals Commission (SIAC), a specialist court which hears challenges to decisions to remove someone's British citizenship on national security grounds, will hold a four-day preliminary hearing in London.
Mrs Justice Elisabeth Laing is expected to deal with, among other things, whether depriving Ms Begum of her British citizenship rendered her stateless and was therefore unlawful.
Individuals appealing to SIAC usually remain anonymous, however it is understood that Ms Begum has waived her right to anonymity.
Ms Begum, then aged 15, was one of three schoolgirls - along with Kadiza Sultana and Amira Abase - from Bethnal Green Academy who left their homes and families in February 2015 to join a fourth Bethnal Green schoolgirl, Sharmeena Begum, who had left London in 2014, in Syria.
In February, Ms Begum was found by The Times, nine months pregnant, at a refugee camp, telling the paper that she would "do anything required just to be able to come home".
Ms Begum said she was married 10 days after arriving in Raqqa to a Dutchman who had converted to Islam, Yago Riedijk, who she claimed was later arrested, charged with spying and tortured.
She eventually left Raqqa in January 2017 with her husband but her children, a girl aged a year and nine months old and a three-month-old boy, both died.
Her third child, a son, also died shortly after he was born.
Ms Begum told The Times she had "mostly" lived a "normal life in Raqqa, every now and then bombing and stuff".
She added: "But when I saw my first severed head in a bin it didn't faze me at all. It was from a captured fighter seized on the battlefield, an enemy of Islam. I thought only of what he would have done to a Muslim woman if he had the chance."
The Home Office revoked her British citizenship later in February - a decision which is only lawful if it did not leave Ms Begum stateless.
It was speculated at the time that Ms Begum may have Bangladeshi citizenship, but Bangladesh's minister of state for foreign affairs Shahriar Alam has denied this.
Home Secretary Priti Patel told The Sun last month that Ms Begum would not be able to return to the UK, telling the paper: "Our job is to keep our country safe.
"We don't need people who have done harm and left our country to be part of a death cult and to perpetrate that ideology.
"We cannot have people who would do us harm allowed to enter our country - and that includes this woman.
"Everything I see in terms of security and intelligence, I am simply not willing to allow anybody who has been an active supporter or campaigner for IS in this country."