Thousands of Doctor Who fans have met their heroes - and villains - at an official convention for the long-running show.

The weekend event at the Wales Millennium Centre in Cardiff attracted aficionados from as far away as the US, Australia and New Zealand.

It included the chance to meet Matt Smith (the Doctor) and his departing assistant Karen Gillan (Amy Pond).

Producer Steven Moffat and production staff were also on hand.

DOCTOR WHO DEVOTEES Doctor Who fans are noted for their devotion. So much that they not only seek autographs from the stars, but also from behind-the-scenes staff, such as Danny Hargreaves, the special effects supervisor, who they have seen in spin-off programmes like Doctor Who Confidential. Hargreaves said: "It's a massive beast, Doctor Who. It's a massive, massive draw for everyone and a very popular show". He is responsible for effects such as explosions and fires, rain and snow, and that can be difficult when filming in real locations such as Cardiff streets. "Everything has its challenges, particularly when you are trying to achieve certain level of effects in urban environments. So it's my job to ensure that everything goes well and safely." One American fan, Guy, told how he and his son had travelled from Massachusetts for the convention. "We lived in England and saw the Christmas special in 2006 and we were completely hooked on this show and continued to watch even after we moved back to the States. "It's a great drama which deals with lots of serious issues but it does so in a cool and interesting way with aliens and things like that." Another, Adam, a film-maker from Reading, said: "Everything from the storytelling to the art direction, acting, the crew, writers, directors, costume designers, props, is fantastic. "One of the great aspects of the show is that the production values and everything changes. It kind of regenerates - excuse the pun - to a new era. "We've just been talking to the art director and costume designer, so it's really nice to get up close to them and talk about their experiences."

Billed as the "ultimate Doctor Who fan event", the convention was limited to 1,500 people each day but promised those who have spent up to £99 for tickets access to the people behind the BBC show.

In Pictures: Doctor Who and fans

Hosted panel sessions included discussions with the key cast members as well as members of the creative team such as directors, scriptwriters and special effects experts.

These include Doctor Who special effects supervisor Danny Hargreaves and his team recreating a battle scene each day with live pyrotechnics, explosions and laser effects.

A prosthetics demonstration took watchers through the process of transforming a person into an alien while a props and costume display included some from the early years of Doctor Who.

Smith will return as the Time Lord in the new series of Doctor Who, which starts later this year.

The convention, running from 09:00 - 18:00 GMT on Saturday and Sunday, was staged by BBC Worldwide.

A spokesperson said: "It's a celebration of creativity, of the script-to-screen process, from the concept and how that gets made in to a script.

"It follows the casting, and the creation of the visual effects and how you get the image the writer had in his head to the episode you see on the TV screen."

The convention has also attracted people from Canada, Norway, France, the Netherlands and Ireland.

The Wales Millennium Centre itself has starred in several episodes, standing in as a hospital in series two episode New Earth, and the building featured in The Girl Who Waited in series six.

Image caption Fans have the chance to meet some of the stars of the show

Some of those attending the convention have already had a tour of the former Tardis set at Upper Boat, near Pontypridd.

The programme is moving to new purpose-built studios at Roath Lock, only yards from the Wales Millennium Centre.

The Doctor Who Experience, which closed in London last month is set to open in Cardiff Bay later this year, featuring sets, props and memorabilia from the series.

It is expected to attract up to 250,000 visitors a year.

Doctor Who began on the BBC in 1963 and was revived by BBC Wales in 2005.