UPDATE 25/3/15 12:00pm After one day, 21 hours, 18 minutes and 29 seconds, the longest ever turn in Hearthstone is now complete.

Twitch user Mamytwink completed his record-breaking feat earlier today - and the game did not crash.

Watch the moment it happened below, from the 36:30 mark.

ORIGINAL STORY 23/3/15 7:35pm Blizzard's virtual card game Hearthstone grants players 90 seconds each turn to make their moves. This turn, though, will take over 40 hours to finish.

The working out, if you dare.

"Mamytwink", playing against an opponent he also controls, set out to break the world record for the longest ever turn in Hearthstone - and he's streaming the results.

It's a pretty complicated set-up. Mamytwink, as a mage, has managed to get seven Prophet Velen cards on his side of the board. He did this using multiple Faceless Manipulator cards, each of which makes a copy of a minion, in this case Prophet Velen.

Prophet Velen doubles the damage of your spells. Seven Prophet Velens means the number of missiles fired is doubled seven times. Each Prophet Velen is then buffed a huge number of times with a variety of cards so that spell damage is boosted even further.

The spell doing the damage is Arcane Missiles, a one mana cost card that's firing off an incredible 28,752 missiles because of the many cards and buffs in play. Nine Arcane Missiles cards have been played this turn, causing a total of 258,768 points of damage.

If you're wondering why the Missiles do not hit the enemy minions, it's because they're already dead. They died a long time ago.

The Ice Block secret prevents the opponent priest from dying this turn.

Mamytwink's spectacular turn is expected to resolve itself when all the Arcane Missiles have been fired. This should take between 40 and 43 hours - if the game doesn't crash first.

At the time of publication the turn had been going for four hours and 20 minutes. Mamytwink had turned off the lights in his room and left his computer running the game.

The important question is: once everything's sorted out, which player will win?