Cobblers have been drawn away to John-Joe O'Toole's Burton Albion in the third round of the FA Cup.
Keith Curle's side will travel to the Pirelli Stadium to take on the Brewers, managed by Nigel Clough, in the New Year.
Burton, currently 14th in Sky Bet League One having won at Sunderland last time out, snapped up O'Toole in the summer after he was released by Northampton at the end of last season.
The 31-year-old played almost 200 games for the Cobblers between 2014 and 2019 and was a key figure in their title success in 2015/16. He's featured 24 times for Burton this season.
Curle's men reached this stage of the competition with wins over non-league teams Chippenham Town and Notts County, while Burton beat Salford and Oldham.
Third round ties will take place over the weekend of January 3-6, which means Northampton's scheduled League Two clash at Leyton Orient on January 4 will be rearranged.
Tony Adams and Micah Richards conducted tonight's draw live on BBC TWO from the Etihad Stadium, home of holders and five-time champions Manchester City.
The FA have also announced that all third-round ties will kick-off one minute late as part of a campaign to promote mental health.
"We know men in particular can be reluctant to talk about the subject, so it is important we use football as a vehicle to stress the importance of mental fitness," FA chief executive Mark Bullingham said.
Draw in full
Leicester City v Wigan Athletic
QPR v Swansea City
Fulham v Aston Villa
Chelsea v Nottingham Forest
Wolves v Manchester United
Charlton Athletic v West Brom
Rochdale or Boston United v Newcastle United
Cardiff City v Forest Green Rovers or Carlisle United
Oxford United v Exeter City or Hartlepool United
Sheffield United v AFC Fylde
Southampton v Huddersfield Town
Liverpool v Everton
Bristol City v Shrewsbury Town
Bournemouth v Luton Town
Brighton v Sheffield Wednesday
Bristol Rovers or Plymouth Argyle v Coventry City or Ipswich Town
Eastleigh or Crewe Alexandra v Barnsley
Manchester City v Port Vale
Middlesbrough v Tottenham
Reading v Blackpool
Watford v Tranmere Rovers
Preston v Norwich City
Millwall v Newport County
Crystal Palace v Derby County
Solihull Moors or Rotherham United v Hull City
Brentford v Stoke City
Fleetwood Town v Portsmouth
Arsenal v Leeds United
Gillingham v West Ham United
Burton Albion v NORTHAMPTON TOWN
Burnley v Peterborough United
Birmingham City v Blackburn Rovers