Nine Inch Nails have sent fans envelopes filled with black powder.

The electronic metal group - Trent Reznor, Robin Finck, Alessandro Cortini, Ilan Rubin and Atticus Ross - caused a stir among their devoted following by having the wrapped substance posted out with direct purchases of their new EP 'Not The Actual Events' from their website.

The bizarre freebie was teased on the site as a so-called ''physical component'' to be included with copies of the record and shocked fans have been left delighted and bemused to discover the mystery dark powder scattered over a series of band photos and texts.

It was also came with a sticker that warned the EP ''may contain subversive elements that produce feelings of euphoria and [which] may be harmful and unsettling to the consumer''.

The sticker also advised: ''This will make a mess.''

Fans hope that the band will announce a tour later this year after they revealed they'll perform for the first time in three years at Panorama Festival in New York in July.

But when asked if there were plans to take any new music on the road in 2017, Trent kept tight-lipped on the matter.

In December, he said: ''Not in the immediate future, but we are discussing it.''

However, fans can expect another musical offering from the 'Closer' hitmaker this year as Trent teased they've completed ''two new major'' records due for release in 2017.

The frontman teased: ''I'm teeing up the next quote I'll have to live up to, but the idea has been for two new major works come out next year.''