The release of the Pokémon Go app has taken the United States, Australia and New Zealand by storm, so much so that its UK launch has been delayed.
Such is the popularity of the new app that just two days after its release in the US it already has more users than dating app Tinder and is soon set to surpass Twitter in its number of daily active users.
But what is all the hype about? What is it? How can you play? And what do you need to know if your children are playing it?
In the 21 years since its 1995 release, Pokémon has changed a lot from the Nintendo Game Boy video games and cards children spent hours in the playground capturing, trading, and battling with mysterious creatures.
Pokémon characters Pikachu and friends are back in a 21st century form: a smartphone app.
What is Pokemon Go?
Pokémon Go is an augmented reality game (computer generated images on the real world when viewed on the phone's screen) which gets people to go out and catch virtual monsters using a person's location on their phone.
How do you play?
You walk around local landmarks - or Pokestops - where you can gather supplies such as Pokeballs.
When you find online "pocket monsters" or Pokémon you throw your Pokeballs at them and capture them for training.
At other locations called "gyms" - Pokémon battle each other for supremacy.
When is it coming to the UK?
The game was released in the US last week, and can also be played in Australia and New Zealand.
However, as the game is so popular, more people have downloaded it and are playing it than its servers can cope with - meaning that the rollout in the UK, Europe and the rest of the world has been paused.
Just how popular is popular?
Within two days of the game's release in the US, the app is now on more Android phones in America than Tinder, according to Similar Web. Think about how many people you know who are on the dating app; Pokémon is taking the world by storm.
In the next couple of days, the game is expected to have more daily active users than Twitter. In America, three per cent of the population are daily active users, and of these, people spend an average of 43 minutes and 23 seconds on it per day, higher than Whatsapp, Instagram, or Snapchat.
The game's popularity helped Nintendo's share price jump by nearly a quarter on Monday, adding £4.5 billion pounds to the company's value.
Perhaps unsurprisingly, Nintendo has said it will launch four more smartphone games by the end of 2017.
Where did the idea come from?
The game began life as an April Fools' Day joke two years ago when Google released this video.
The video was a fake introduction into a new part of Google Maps and Niantic Labs who created the game (along with Pokémon Company) was originally part of Google.
John Hanke, who was vice president of Google Geo division at the time and now runs Niantic Labs, said everyone loved it, and then one thing led to another...
Have there been any issues with the game?
Armed robbers have used the game to lure victims to a deserted car park in the US state of Missouri.
Using the geolocation feature of the game, the suspects were thought to have been able to anticipate the location and level of seclusion.
At a certain level of the game players can also add a beacon to a Pokestop to lure players there to join teams and battle.
Players of the game should be aware of their own safety when playing it.