The celebration, celebrated every three years in a different country, is taking place in Krakow.
Revd David Brown, from Res Sacra Miser Chapel in Warsaw, told Premier: "95% of the population are Catholic, in inverted commas.
"They are finding, like many churches throughout the western world, that they are not really relating to young people, so I think they feel this is a wonderful opportunity to get young people involved.
"If you have got young people being involved in this week, in a sense it is up to the Church to so use the week and so inspire the young people so that they do actually want to continue their involvement with a Christian life after the end of the week."
Pope Francis (above) has also sent a personal message to young people ahead of World Youth Day.
He said: "The 31st World Youth Day is fast approaching.
"I look forward to meeting the young people from throughout the world gathered in Krakow and having the opportunity to meet the beloved Polish nation.
"My entire visit will be inspired by Mercy during this Jubilee Year, and by the grateful and blessed memory of Saint John Paul II, who instituted the World Youth Days and was the guide of the Polish people in its recent historic journey towards freedom.
"I thank you heartily for everything that you have done, and for the love with which you have done it. Even now I embrace you and I bless you.
"Dear young people from throughout Europe, Africa, America, Asia and Oceania!
"I also bless your countries, your hopes and your journey to Krakow, praying that it will be a pilgrimage of faith and fraternity."
Click HERE to go to our official World Youth Day page!
