The LaLiga giants were desperate to land the then highly-sought after midfielder - with clubs across Europe vying for his signature - Bostock was even sent a signed Ronaldinho in a bid to land him.
"When I was 14, Barcelona offered me a ten-year contract," Bostock told BBC Sport.
"Ronaldinho was my favourite player at the time so they sent me a signed poster from him. I've still got it at my house in London. It said, 'To John from Ronaldinho.'
"You name the club, I had interest from them. Barcelona, Real Madrid, Inter, Manchester United, Chelsea, Liverpool - the who's who of European football.
"From as early as I remember I wanted to be the best player in the world and to win the Ballon d'Or.
"I saw Ronaldinho win these trophies and I just thought I want to be that guy. I pinned my identity on that and I thought if I didn't achieve that I was a failure."
Bostock ended up remaining at Selhurst Park and made history when he became the youngest player to feature for the club when he made his professional debut aged 15 years and 287 days.
The £700,000 transfer to Tottenham which followed sparked fury among many personnel at Palace - none more so than then chairman Simon Jordan.
Bostock was released by Spurs in 2013 and in total has featured for 13 different clubs spanning a 13-year period.
Among them have been loan spells at Brentford, Hull and Sheffield Wednesday.
Bostock did enjoy relative success in Belgium and France with OH Leuven and RC Lens respectively, but then largely flattered to deceive at both Bursapor and Toulouse.
The 28-year-old left the latter by mutual consent in October and is now on the hunt for a new club, ideally in England.
Former Crystal Palace wonderkid John Bostock has revealed he rejected a ten-year contract from Barcelona when he was just 14 years old.