The Tottenham winger, 22, was unavailable through injury when the two sides met at Millennium Stadium in March, a match which England comfortably won 2-0.
The Italian coach, whose contract with the Three Lions ends after Euro 2012, has pinpointed the left-sided player as the opposition’s main threat.
“Bale always makes a difference. He is a really, really, important player for Wales,” Capello told reporters.
“We need to find a system to stop him and stop people passing to him.”
He added: “We need to be very careful every time he receives the ball.”
Welsh manager Gary Speed will see his side go into the game as overwhelming underdogs, with 113 places between his team and fourth-placed England in the Fifa rankings.
But despite their lowly position, Wales beat Montenegro 2-1 in their home clash on Friday, whilst England could only manage a 0-0 draw against the eastern Europeans when they came to Wembley last season.
Capello believes Bale was in menacing form in their home win a few days ago and far more threatening than in his last game for Spurs against Manchester City.
The Italian said: “I have watched [Wales'] game against Montenegro and he played really well. He is a really good, important player.
“I watched the game he played when Spurs played against Man City and he was so-so. He was not at the top of his form, but in the game he played with Wales against Montenegro he had improved a lot.
“He ran a lot, was really fast. It will be a problem to stop him because it is difficult when he receives the ball and attacks the space.
“He's fast and technically he is fantastic. He can play left or right – a very good player.”