Ali Hewson believes EDUN's collaboration with Diesel is ''thoughtful and sexy''.

The two companies have teamed up for a 25-piece ethical collection, Diesel + EDUN - which is all manufactured with Concervative Cotton Initiative (CCI) cotton from Uganda and modelled by African 'trailblazers' - and the designer thinks ethical fashion has changed a lot since she launched her company in 2005.

She said: ''Both ethical and sustainable fashion have come a long way from when we first launched EDUN in 2005. At the time there were very few people doing it with a design focus in mind.

''We knew that fashion is the 'want' business not the 'need' business, so great design is key.

''The Diesel + EDUN collection is thoughtful, sexy and it's 100 per cent made and sourced in Africa. That's how we want to keep moving forward.''

Ali - the wife of U2 frontman Bono - thinks the collaboration is ideal as EDUN have a ''big voice'' in ethical fashion and Diesel allows them to take that out on a wider scale.

She told Grazia magazine: ''At EDUN's inception, we always intended to collaborate with other businesses. We are a small company, but we have a big voice.

''We want to encourage more business growth and trade with the people of Africa.

''Also, as a small company we only produce small quantities, but with Diesel, we have an opportunity to create a volume of pieces and, hence, more trade.''