Ashley Olsen, Mary-Kate Olsen in a still from New York Minute (2004/I).

Actresses turned fashion designer sisters Ashley Olsen and Mary-Kate Olsen are set to add a new clothes line 'Elizabeth and James' to their couture label, 'The Row'.

The new collection is reportedly named after the twins' siblings and is influenced by their own vintage collection.

The fashion moguls insisted that the concept of their designs has been taken from a boy and girl relationship.

"We wanted it to be based on a relationship between a young girl and a boy and tell the story through the clothing,¡± US Weekly quoted the Oslens, as telling Women's Wear Daily magazine.

The new collection will be on sale at Neiman Marcus, Bergdorf Goodman, and Intermix from the fall.

Mary-Kate and Ashley have a clothing line in Wal-Mart stores across America for girls aged 4-14, as well as a beauty line called 'Mary-Kate and Ashley: Real fashion for real girls'.