Phoebe Dahl found ''love at first sight'' with her fiancee Ruby Rose.

The British designer - who's grandfather is children's author Roald Dahl - got engaged to the 'Orange is the New Black' actress within months of meeting and revealed that the couple have been inseparable ever since.

She gushed: ''Do I believe in love at first sight? I didn't before Ruby but now I do. I have to! It happened to me.

''I met Ruby at a barbecue I threw a year and a half ago and we got engaged within about three months. It was all very instant... Honestly, we're not really apart that often.''

Phoebe, 26, is planning a ''big'' wedding to the Australian beauty, 29, but the couple are busy with their careers in fashion and showbiz.

She said: ''We're enjoying being engaged. Ruby wants a low-key wedding but I want a big one. I'm from a family of 50 so it's going to have to be big. I don't know how anyone has time to plan a wedding, we're both so focused on our careers right now.''

Meanwhile Ruby, 29, is a representative of LGBT rights and both women want to use their star status to promote issues close to their hearts.

Phoebe told Hello! Fashion Monthly: ''I know our lives will change a little bit but we're both very modest and humble so I don't think it'll affect us too much. If anything, we'll be able to use the spotlight to shed light on greater world issues.

''I know Ruby will use it to touch on LGBT issues and hopefully I'll be able to promote my causes, which are sex trafficking, girls' education and women's empowerment.''

The full interview with Phoebe appears in the September issue of HELLO! Fashion Monthly - on sale 4th August.