Pearce has revealed that his request to name Arsenal's rising star in his squad for this month's two-legged European Championships play-off against Wales left Capello laughing.
Pearce knew it was a long shot after Walcott's hat-trick in the World Cup clash against Croatia last month.
The 19-year-old is now a key man in senior coach Capello's plans for the forthcoming qualifiers against Kazakhstan and Belarus.
That makes him unavailable for the first leg against Wales at Ninian Park on October 10 and the return at Villa Park on October 14.
Pearce revealed: "Fabio never answered my question as he burst out laughing.
"But bear in mind I did ask him the question in the dressing room in Croatia. I thought I would strike while the iron was hot!"
Pearce, however, is more than hopeful that Walcott will be available to play in the finals in Sweden next June - providing England get past Wales.
He said: "I want Theo to represent the under-21 side next summer and I cannot see any problem."