Stefano Gabbana has slammed Sir Elton John as a ''fascist'' and ''ignorant'' after the singer encouraged people to boycott Dolce and Gabbana over their opinions on gay adoption and children born through IVF.

The 52-year-old designer - who runs fashion house Dolce and Gabbana with business partner Domenico Dolce - admitted he ''didn't expect'' such a backlash after the pair branded kids conceived through fertility treatment ''synthetic'' and admitted they ''opposed gay adoptions''.

Stefano also hit out at Elton - whose two sons Zachary, five, and Elijah, two, with husband David Furnish were conceived through IVF treatment - for ''attacking'' the pair, who were in a relationship for 25 years until 2005, for having a ''different opinion'' to him.

Speaking in Italian daily newspaper Corriere della Sera, he said: ''I didn't expect this. I didn't expect this, coming from someone whom I considered, and I stress 'considered,' an intelligent person like Elton John.

''I mean, you preach understanding, tolerance and then you attack others? Only because someone has a different opinion? Is this a democratic or enlightened way of thinking? This is ignorance, because he ignores the fact that others might have a different opinion and that theirs is as worthy of respect as his.

''It's an authoritarian way of seeing the world - agree with me or, if you don't, I'll attack you.

''I even posted the word 'Fascist!' on his Instagram.''

Stefano also claimed he and Domenico had words ''put into their mouths'' and insisted it was ''preposterous'' that people have vowed to boycott their brand because of the comments.

He added: ''It would be ridiculous. Either you like somebody's songs or you don't. When you go to the greengrocer's, you don't make sure that he agrees with your views on IVF. You just want to know if he has fresh products.

''This whole campaign came up online. It was created by a group of gay activists who put into our mouths words we never said. It became bigger and bigger. We are not boycotting and we will not boycott anyone.

''It's like people who go to a football game to insult their opponents. That doesn't make any sense. That's preposterous.''

Dolce and Gabbana initial comments appeared in Italian magazine Panorama, in which they were quoted as saying: ''We oppose gay adoptions. The only family is the traditional one.

''No chemical offsprings and rented uterus: life has a natural flow, there are things that should not be changed.''

Following the article, Elton took to his Instagram account to slam their remarks.

He wrote: ''How dare you refer to my beautiful children as ''synthetic''. And shame on you for wagging your judgemental little fingers at IVF - a miracle that has allowed legions of loving people, both straight and gay, to fulfil their dream of having children.

''Your archaic thinking is out of step with the times, just like your fashions. I shall never wear Dolce and Gabbana ever again. #BoycottDolceGabbana (sic).''

Several stars have also come out in support of Elton including Victoria Beckham, Ricky Martin, Martina Navratilova and Courtney Love, who admitted she wants to ''burn'' all of her Dolce and Gabbana clothing.