The SNP are on course to win 55 seats, up 20 and their second best result of all time.
All the Scottish party leaders are out on the campaign trail ahead of Thursday's election.
The debate will be broadcast live on STV at 8pm on Tuesday night.
Politicians will seek to win over Scotland's voters as they gear up for the general election.
Jackson Carlaw has ruled out the prospect of indyref2 during Boris Johnson's premiership.
The First Minister is expected to make the comments in a speech to party activists on Saturday.
An Ipsos MORI survey found 44% of voters will pick Nicola Sturgeon's party on December 12.
Scots candidate Sebastian Leslie appeared on Scotland Tonight, calling for a no-deal Brexit.
The party is pledging 'no to indyref2' as its pitch to voters ahead of the December 12 poll.