The poster ads, created by Rainey Kelly Campbell Roalfe/Y&R, launch on Friday, and show Dahl in a series of portraits wearing a charity T-shirt, shot by photographer Giles Bensimon. Dahl and Bensimon gave their time to this project for free.
Dahl said: "I am thrilled to be involved with this innovative fashion campaign which has historically achieved so much for Breakthrough Breast Cancer's research, education and tireless campaigning work."
The campaign, which Rainey Kelly Campbell Roalfe worked on last year as well, uses a series of slogans including: "Sophie Loves Hers", "Support Wanted" and "For the Love of Boobs". These match the different poses in the ads, and the letter "o" is replaced with the target symbol on the T-shirt.
Dahl is most famous for taking her clothes off for a Yves Saint Laurent perfume ad, which featured Dahl wearing nothing but a pearl choker and gold stilettos. The ad in December 2000 received 730 complaints. It was banned by the ASA.
For the first time, this year's campaign also includes an ad targeted at men that uses male model James Piper. The ad encourages men to join the girls and support the charity.
All media has been donated and this year a heavy-weight outdoor campaign including bus sides, 96 sheets, 48 sheets and six sheets, will be supported by press activity to create as much noise around FTBC 2007 as possible.
Chris Askew, director of fundraising at breakthrough breast cancer, said: "We decided to work with RKCR/Y&R again this year because they are a leading agency for awareness-raising campaigns, and their work on Fashion Targets Breast Cancer has been effective and successful year-on-year in raising the profile of our flagship campaign. We are confident that the 2007 ad campaign will do the same and help Breakthrough take one step closer towards its vision of a future free from the fear of breast cancer."
Fashion Targets Breast Cancer is a worldwide initiative inspired by fashion designer Ralph Lauren in 1994. Last year nearly 44,000 women were diagnosed with breast cancer, each year 13,000 women will die of the disease.
Since Breakthrough launched FTBC in the UK in 1996, it has raised over £7.5m from the sale of charity T-shirts and other merchandise.
FTBC is sponsored by Marks & Spencer, Nissan and River Island.