Boris Johnson and Jeremy Hunt will take part in a final showdown debate hosted by talkRADIO and The Sun on Monday night.
It will be one of the duo's last chances to win over 160,000 Conservative Party members in the four-week long leadership contest.
The 90-minute debate will be held at talkRADIO's London Bridge headquarters from 7pm.
Mr Hunt was the first to agree to take part in the debate, followed by leadership frontrunner Mr Johnson.
Mr Johnson said he was "delighted" to be taking part, and is keen to share his "vision" for delivering Brexit.
The final deadline for party members to vote for their next leader and Prime Minister is July 22.
The winner is expected to be announced on July 23.
Theresa May will stay in office until July 24 to spare her successor fierce questioning from MPs at Prime Minister's Questions.