Hollywood superstars Brad Pitt and Angelina Jolie are setting their sights on a spring wedding. The couple, who have been together for seven years and have six children, are discussing holding the service in Brad\'s home town of Springfield, Missouri — but don\'t expect a traditional celebration. Pitt, 48, and Jolie, 36, have set their hearts on a spiritual ceremony incorporating traditions from the different countries where their children were born. Three of the couple\'s brood are adopted: Maddox, ten, is from Cambodia; Pax, eight, is from Vietnam; and Zahara, seven, is from Ethiopia. Their biological daughter Shiloh, five, was born in Namibia and three-year-old twins Vivienne and Knox in Nice. \"The ceremony will be low-key with just family and friends invited,\" says a friend of the couple. \"Angelina wants her father Jon Voight and her brother James Haven to be a part of the day. \"They are keeping their cards close to their chest. The ceremony will by no means be a showbiz event. They want total privacy. All the children will be involved — Brad and Angelina have been researching weddings in the countries where their children were born.\" Because neither Pitt nor Jolie is religious, the ceremony will be spiritual. Says the source: \"It won\'t be a church service but it will incorporate all the cultures within their family.\" Pitt raised the prospect of marriage recently, telling a Hollywood magazine: \"We\'d like to and it seems to mean more and more to our kids.\" The couple — nicknamed Brangelina — started dating after meeting on the set of Mr & Mrs Smith in 2004. Pitt was previously married to Friends star Jennifer Aniston, while Angelina has been married to actors Jonny Lee Miller and Billy Bob Thornton.