Rihanna's debut fashion line with River Island is now on sale, and the pop star was in London to officially launch the collection.

Pop superstar Rihanna has admitted she was a "little bit selfish" when she was designing her range of clothing for River Island - a career move she referred to as "the dream".

The singer, who arrived about an hour late for the launch of her fashion collaboration in central London last night, said she made sure all of her designs were pieces she would want to wear herself.

She said she hoped they would still be fashionable a decade from now.

After a catwalk show at the Oxford Street shop in which models strutted down a runway and posed in the front window wearing clothes from the collection, Rihanna took a stroll around to see her designs hanging on the high street store's rails.

Dressed in a tight, floor-length black gown and with her hair hanging in loose curls over one shoulder, the Barbados native stopped with waiting journalists to chat about her latest venture.

As she examined the garments on display, she exclaimed: "This is the dream!"

The 25-year-old star said she was in disbelief as she reflected on the creative process, all the while admiring the cropped tops, slashed-to-the-thigh dresses and bright neon colours.

"From where we started, from jotting these down on napkins and pieces of paper in the hotel room in the middle of the night. It's scary.

"I mean, I'm so happy. I can't even believe it," she said.

Rihanna said her clothes were aimed at a variety of women, but said they are all pieces she would wear herself.

She said: "I would wear everything here. I was being a little bit selfish.

"I designed everything that I would want to wear, and for the women that I'm with.

"I'm with a large group of women who have different sizes, different tastes, different body types.

"I wanted to design something that everybody could wear because I wanted all my friends to have something too, but I'd still wear everything."

Rihanna said that while the women her clothes are aimed at should have a "fun" relationship with fashion, she wanted her pieces to be timeless.

Speaking about the typical woman she is hoping to dress, she said: "Sassy, fun and someone who's not afraid of having fun with fashion, but everything is simple, everything is classic.

"I wanted to make things that ten years from now we'll not know what era, they'll not have an era attached to it or a brand or whatever," she said.

Fans queued outside River Island hoping to catch a glimpse of the star, while fashionistas were able to see the fashion collection at her London Fashion Week show last month.