British Prime Minister
Her speech on Tuesday will lay out "more on our approach to Brexit, as part of preparing for the negotiations and in line with our approach for global Britain and continuing to be an outward-looking nation", her spokeswoman said.
May has said she intends to begin formal exit negotiations by the end of March. Triggering Article 50 of the European Union's Lisbon Treaty begins a two-year countdown to leaving the bloc.
The Conservative leader has so far resisted demands for more detail on her strategy, but has been clear she wants to limit control of migration from the rest of the EU.
Bloc leaders have insisted that Britain cannot "cherry-pick" which aspects of its membership to maintain, and have also warned that limiting migration is incompatible with staying in the single market.
Britain's former ambassador to Brussels, Ivan Rogers, revealed he was still in the dark on her plans when he expectedly resigned from his job earlier this month, warning of "muddled thinking".
As May's self-imposed March deadline approaches, MPs, businesses and commentators on all sides of the Brexit debate are calling for more detail on the potential shape of Britain's future relationship with the EU.
In a referendum on June 23 last year, Britons voted by 52 percent to end their country's four-decade membership of the EU.