Lisbon Lion Bertie Auld has told Celtic chiefs to remember entertaining the Parkhead support is more important than money while they weigh up whether to cash in on Moussa Dembele.
West Ham were last week linked with a £20million swoop for the 19-goal Frenchman.
But with English Premier League clubs awash with television riches, the Hoops will be in no rush to accept the first offer for a player who cost them just £500,000 when he arrived from Fulham in the summer.
Auld, though, has urged Celtic chief executive Peter Lawwell to think twice before selling.
Having banked upwards of £25million from this season's Champions League run, the European Cup winner insists his old side have no need to offload their top scorer.
And he believes Celtic should reward their passionate supporters for their backing by rejecting all bids for Dembele - no matter how high they go.
Asked how much the 20-year-old was worth, Auld said: "I don't think that should come into the matter. What we don't need is money.
"But what we do need is quality on the park because for this support, we must keep our good players. If it was a dumpling, you'd let them go. But no, we must keep the quality.
"When I see Dembele, I'm reminded of something my dad told me when I was 16. He said to me, 'Bert, if you can play and entertain this support, they will never forget you'.
"Things don't change."
Auld was part of the Jock Stein side which swept the rest of Scottish football aside before conquering Europe in 1967.
This year is the 50th anniversary of that incredible season - a campaign which also saw the quadruple-winning Hoops set a post-war record run of 26 domestic games without defeat from day one of the season.
Ulsterman Brendan Rodgers' current crop can beat that mark if they emerge unscathed from their next three clashes - a William Hill Scottish Cup tie away to Albion Rovers and Ladbrokes Premiership fixtures at home to St Johnstone and Hearts.
Auld, 78, said: "I hope they break the record because the most important people are those supporters, who deserve to see it.
"Have you ever seen numbers like them in your puff? Home and away they turn out."