Guardiola says Real Madrid are a different proposition with Bellingham
Holders City beat the 14-time Champions League winners in the Champions League semi-finals last season, drawing 1-1 away and securing a thumping 4-0 win at the Etihad in the second leg.
Bellingham, who joined Real from Borussia Dortmund in July for a fee of around 103 million euros (£88 million), has scored 20 goals and set up nine for the Spanish side across all competitions this season.
Asked about the leading La Liga goalscorer, the City manager told reporters on Friday: "(Bellingham's) impact has been massive. It's a different team from last season. His influence is obvious, and we have to try to discover what he does to control it.
"Facing Real Madrid is always a tough challenge, nobody can deny it. They are an exceptional club, and in this competition they can control many things with the experience they have in the past.
"Like last season there will be moments for them and moments for us. The longer we can keep our moments, we'll be closer. We'll try to do a good performance in Madrid and then here, with our people, do it again."
The first legs of the Champions League's quarter-finals will be played from April 9th-10th and the second legs on April 16th-17th.
City play Newcastle United in the FA Cup quarter-finals on Saturday and face Arsenal in the Premier League after the international break.