The Italian expected the clash with the reigning World Cup and Euro champions to be held on Friday but it was shifted to allow more time for Barcelona's players to recover from a mid-week match.
The switch was agreed by England general manager Franco Baldini but he was unaware that Capello's son Pierfilippo was due to get hitched on Saturday.
Capello's wife Laura will attend their 36-year-old son's big day while the former AC Milan and Real Madrid boss will wear a special flower in his lapel at Wembley Stadium.
Capello is expected to be on the touchline as his son is married to his long-time partner and mother of his two children, Tiziana.
Speaking to The Independent, Pierfilippo said of his father missing the wedding: "It is not a problem, absolutely not.
"He is a football manager first; he has been that ever since I was a child and sometimes being a football manager can make strange demands on your time.
"You just have to accept that.
"We will all toast him sitting there on the bench at Wembley and look forward to him coming to join us for the celebrations after the games."
