The 23rd World Youth Day 2008 was a Catholic youth festival that started on 15 July and continued until 20 July 2008 in Sydney, Australia. It was the first World Youth Day held in Australia and the first World Youth Day in Oceania. This meeting was decided by Pope Benedict XVI, during the Cologne World Youth Day of 2005. The theme was "You will receive power when the Holy Spirit comes on you" (from Acts 1:8).

About 500,000 young people from 200 countries attended during the week, and more than 1,000,000 came for the weekend. They were joined by about 600 bishops and cardinals, as well as by 6,600 reporters.

The festivals of WYD began on 1 July 2007, when a large 3.8-meter-high wooden Cross and a large 15-kilogram Icon of the Virgin Mary arrived in Sydney to travel around the country. The relay-style event, known as the Journey of the Cross and Icon (or JCI for short) saw the cross and icon go on a pilgrimage around the dioceses of Australia, engaging with a variety of Catholic parishes and communities.

World Youth Day (commonly abbreviated to WYD) is a youth-oriented Catholic Church event. While the event itself celebrates the Catholic faith, the invitation to attend extends to all youth, regardless of religious convictions.World Youth Day is not associated with International Youth Day or any of the international observance days.

World Youth Day was initiated by Pope John Paul II in 1985. It is celebrated diocesan level annually, and at a week-long international level every two to three years at different locations. The international level events attract hundreds of thousands of youth from almost every country on the planet. It is a major part of the upsurge in Catholic Youth Work in some countries over recent years; for example, the Director of Catholic Youth Services for England and Wales has said of the event that it would have far-reaching effects, not restricted to those who attended.

The Church has officially designated Mother General of the Missionaries of Charity, Teresa of Calcutta and Pope, John Paul II as the Patron Saints of the event.

Guy Theodore Sebastian (born 26 October 1981) is an Australian pop, R&B, and soul singer-songwriter who was the first winner of Australian Idol in 2003. Since 2010 he has been a judge on Australia's The X Factor. Sebastian has released six top ten platinum/multi-platinum albums, including a number one and two. He has also released 11 top 15 singles, including eight top tens, with five achieving number one. He has the most number one singles for an Australian male artist in Australian music history, and is equal third overall for all Australian acts. Four of his singles have reached multi-platinum certification, with "Angels Brought Me Here", "Who's That Girl" and "Don't Worry Be Happy" achieving 4× platinum. "Angels Brought Me Here" was the highest selling song in Australia last decade. With 30 platinum and two gold certifications and combined album and single sales of over 2.2 million in Australia, Sebastian has the highest certifications and sales of any Australian Idol contestant.

"Angels Brought Me Here" also reached number one in four Asian countries and New Zealand. Sebastian had a second number one in New Zealand with "Who's That Girl", two other top ten singles and a number three album, and gained four platinum and two gold certifications there. He has worked with a number of well-known American musicians. He co-wrote songs with Brian McKnight and Robin Thicke for his album Beautiful Life, which also included a duet with Mýa. The Memphis Album was recorded with members of the MGs including Steve Cropper, and they were his band on his 2008 Australian tour. Like It Like That has three tracks with John Mayer on guitar and backing vocals, and "Art of Love" featuring Jordin Sparks. "Who's That Girl" from his album Twenty Ten features US rapper Eve.

Matthew "Matt" Guion Maher (born November 10, 1974) is a contemporary Christian music (CCM) artist, songwriter, and worship leader originally from Newfoundland, Canada, who later relocated to Tempe, Arizona. He has written and produced five solo albums to date. Three of his albums have reached the Top 25 Christian Albums Billboard chart and four of his singles have reached the Top 25 Christian Songs chart. He is a practising Catholic.

Maher was born and raised in Newfoundland, Canada. His parents recognized his musical talent, and he grew up taking piano lessons and immersing himself in a broad variety of music and playing in concert and jazz ensembles, singing in a choir, and playing in a garage rock band.

Maher received a scholarship from the Jazz Department at Arizona State University, where he studied Jazz Piano and got his music degree. He paid for his first three years of college by playing piano in a hotel.

Matt currently lives in Tempe, Arizona. He is involved in building community at Our Lady of Mount Carmel parish. He married Kristin Fisher on September 10, 2010. Their son, Michael Conor, was born on August 1, 2011.