Scottish publication 'The Daily Record' reports that 17 Premier League sides will be represented at Parkhead as teams give left-back Kieran Tierney and striker Moussa Dembele the once over.
The pair are valued at over £50m by the Scottish side, with the likes of Manchester United, Liverpool and Arsenal all thought to be amongst the interested parties.
The same source also claims that a Spurs scout was in the crowd for the reverse fixture between the sides and will once again be present on Tuesday.
Should Celtic opt to cash in on Dembele they will be guaranteed a significant profit given that they signed the player on a free from Fulham last summer.
The 21-year-old significantly enhanced his reputation in his maiden season in Soctland and has scored 37 goals in 59 appearances so far for the club.
Tierney meanwhile will be a much more difficult player to sign, given that he put pen to paper on a new six-year deal on Monday.
The player is highly-rated by both club an country and is expected to go on to have a long and successful career in the game.