The Irish conceded just one try in their first three games but leaked three in Saturday's 25-24 victory over Wales that set up a Grand Slam showdown with Clive Woodward's men in Dublin this weekend.
"The hype will be there and we'll have to deal with it, but we'll just set our sights and take it day by day," said O'Kelly, aware of the need for a major improvement.
The giant second rower acknowledges that the focus this week will be on Ireland's defensive coach Mike Ford as they plug the gaps that almost wrecked their Grand Slam dream.
"We know what we need to do," added O'Kelly. "We're going to analyse Saturday's game and see why there were so many holes in our defence.
"But, just because there were holes against Wales doesn't mean there will be holes (against England). We will have a different plan when we play England."