Stella Mccartney's ''personal obsession'' has always been lingerie.

The 45-year-old fashion designed has secured a license with ISA Spa, which will see the firm create, produce and distribute underwear and swimwear collections in keeping with Stella's eponymous brand's ethics.

And the creative mastermind is excited by the partnership because she has always loved the products, and she hopes her customers will also enjoy wearing her garments, which will leave them feeling ''confident and comfortable''.

Speaking to WWD about her partnership and the upcoming capsules, the mogul said: ''Lingerie has been a personal obsession of mine for a long time and I have always been inspired by it. While for swimwear I want to encourage women to feel confident and comfortable about themselves and in what they are wearing.''

And Stella believes the additional products that her eponymous brand will be launching next year marks an ''important new chapter'' for her fashion house.

She continued: ''This is an important new chapter for us at Stella McCartney and I feel that we have found the perfect partner for us, who really understands our brand and will bring together quality, ability and a high level of commitment to take us to this next chapter.''

The mogul's - who is the daughter of music legend Sir Paul McCartney - collaboration with ISA Spa will see them build the new product, and grow the company globally.

Speaking about the joint venture, the chief executive office of ISA Spa, Mila Zegna, said: ''Our mission is to support the brand DNA, core values and social responsibility beliefs thanks to a team that leverages our product know-how, luxury market knowledge and a dedicated sales strategy.''

However, this is not the first time Stella has released a lingerie line as in 2008 she launched a range of undergarments, which developed into a sleepwear range, and included a double mastectomy post-operative bra, as well as a limited edition set to raise awareness for Breast Cancer, which was followed by a beachwear range eight years later.