The Duchess of Cambridge is “no Princess Diana,” says Paul Costelloe, a favorite designer of the late princess.

The Dublin designer’s career has spanned three decades, and he still works with members of the royal family, including Zara Phillips and Princess Anne.

"She’s low key at the moment," he told the Irish Independent, when asked about Kate.

"She started off as another Princess Diana, but I think I got the right one. I was lucky to have Princess Diana as my epitaph. Kate is lovely, but she’s no Princess Diana.

"Different backgrounds, different everything. She's obviously very obedient and carries out the royal message. She won't be running around and hanging out with Elton John anytime soon."

Costelloe said he is happy to work with anyone, not just high profile clients.

"I would love to with anybody whose relevant, if you feel like coming to my little studio in Baker Street," he explained.

"I haven’t been received any phone calls. My main concentration is working on my catwalk show for next September, my Dunnes [Stores] winter collection and I'm just back from Portugal last night."

The designer has recently launched his Spring/Summer Pembroke Jewellery collection. 

"It’s still carrying a very specific look, it's very feminine, it’s certainly not aggressive," he said. "It's very discreet really. It has a lovely attitude.

"I find it hard to talk about jewellery, it's how it's worn. The simplicity of its shape is part of its success. It's pretty reasonably priced for proper jewellery - it's not costume jewellery.

"It’s very sensitive socially to the Irish market, where it's mainly sold. You won't be attacked on your way home from the DART for your diamonds. where it’s mainly sold.

"There are a lot of safety factors involved too."

Costelloe says he likes to walk the streets of Dublin to keep a fresh perspective.

"Paul Costelloe products are never outrageously overpriced or luxurious, I’m still a ready-to-wear designer and I enjoy doing that. I enjoy dressing people of many ages and not depending solely on income.

"I feel that’s what given me the most enjoyment. or Moore Street, I don't walk down Grafton Street...I'm in touch with reality of lives and I enjoy that part, it suits my personality.

"I don’t travel premier class or stay at luxury hotels. Having a large family keeps you focused on how we have to survive. It's tough out there."