Pilgrimage: The Road through Portugal is set to air on BBC Two in the spring and will see celebrities of different faiths and religions take on the northern route of the Fatima Way in Portugal as they discuss what their spirituality means to them.
Trekking the Catholic pilgrimage route are actor Pollard, who was raised Church of England; Rita Simons who is Jewish; Pentecostal Born-Again Christian and Boyzone star Lynch; reality TV star Pattison who is agnostic; Bobby Seagull, a practising Catholic, maths whizz and TV personality; Nabil Abdulrashid, a comedian and practising Muslim; and Paralympian skier Millie Knight, who is non-practising Church of England.
Pattison said: "I've never used the word pilgrimage in my life. I don't think I know what this means but as you get older, your life becomes smaller and that's okay, but you can quickly become stagnant, and I don't want to be stagnant. I want to constantly be growing and evolving and becoming better.
"I think by challenging myself and by getting out of my comfort zone, that's when I can broaden my horizons. I know there'll be some differing viewpoints, some faiths I'm not familiar with, some opinions that are probably different to mine, but I think the key to us all getting along is just understanding."
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Lynch added: "I am a Pentecostal Born Again Christian. My relationship with God is very tight and I love it.
"The reason why I'm taking on this pilgrimage is just to find a bit of clarity in my life. I want to put myself into a position that I've never experienced before and hopefully find out some amazing and emotional things, so this pilgrimage for me is all about the knowledge I can gather, and about my God. This will be big walk for sure, for many reasons."
This is the fifth season of Pilgrimage, but the first one where the celebrity trekkers will be on a deadline as they need to arrive at the Sanctuary in the city of Fatima, one of the biggest Catholic pilgrimage destinations in the world, in time for a celebration and candlelit vigil along with 70,000 other pilgrims from across the globe.
Along the 364km pilgrimage route, they will pass UNESCO world heritage sites, the stunning Portuguese countryside, and stay in basic camps for 15 days as they explore each other's faiths.
Former EastEnder Simons said: "I'm not entirely sure how comfortable I am about revealing to the Jewish community how little I practice the religion. I do think it's very important to know who you are, regardless of how people may judge you and I am comfortable at 45 with who I am."
Seagull added: "I've reached a crossroads in my life where faith has played a big part, but at stages it has drifted. I would like to understand whether faith can play a big part in my life going forward, and undergoing this pilgrimage is the greatest opportunity I will have.
"It's rare in life that we have a few days, let alone a couple of weeks to really look into ourselves in that manner. I'm hoping there could be a new Bobby at the end of this experience."