The band launched the brew in 2013 and it became a big hit with music and beer fans alike.

To celebrate the latest milestone, Bruce Dickinson and his bandmates are brewing up a special limited edition version, called Trooper 666.

The "supercharged" version of the beer will be available later this year (15).

Singer DICkinson says, "Our fans have been asking for a stronger brew and it seemed only right to do this at 6.6 per cent ABV... I think it tastes tremendous, and I personally prefer this straight from the fridge."

Explaining the name of the new brew, he adds, "Despite the links with our song The Number of the Beast, the name Trooper 666 has actually come about as a result of some detailed research by historian Terry Brighton, who has shown that there were in fact 666 soldiers that rode in the Charge of the Light Brigade during the Battle of Balaclava in 1854, and not just the 600 of (Lord Alfred) Tennyson's famous poem."