The 37-year-old singer will release a clothing range inspired by his grandfather in the UK from September.
Robbie's collection, called Farrell, will be available on the website Shopdirect.com and from the House of Fraser department store.
A spokesperson for the brand told Drapersonline.com: 'Future collections will be available across Europe.'
Prices for the line are said to range from £35 to £350.
According to a source, Williams, who recently began a tour with his old group, has an active role in the business.