Eight-time winners Chelsea reached round five courtesy of a comfortable 3-0 victory over Sheffield Wednesday on Sunday.
Dyche's men found themselves on the end of an FA Cup mauling at Manchester City on Saturday but the Clarets boss is convinced they will recover in time for another daunting task.
Former Worthing, Bognor and Eastbourne Borough centre-back Demetriou was also part of the County team that beat Leeds United in the competition last season before bowing out against Tottenham Hotspur in a replay at Wembley.
Having left North London with a tactically flawless win over Arsenal, in the Fourth Round on Friday night, Ole Gunnar Solskjaer will take his side back to the capital for an arguably bigger tie in the last 16 after the twelve time winners were drawn against Chelsea this evening.
League One AFC Wimbledon, who knocked out top-flight West Ham United, take on Championship (second-tier) Millwall, who eliminated Everton in the fourth round. Watford will also be away against the victor of Portsmouth and Queens Park Rangers and are favourites in that game.
Bristol City v Shrewsbury or Wolves. Chelsea vs Manchester United, Swansea City vs Barnet or Brentford, Portsmouth or QPR vs Watford, Brighton or West Brom vs Derby County.
- Ties to be played from February 15-18.