The pair are broadcasting from a secret location somewhere in the UK and are challenging listeners to work out where they are - and plenty think the pair could be holed up in Sheffield.
Last night and this morning they've revealed a number of facts about where they - and many fans reckon that points to Sheffield.
They include that they are in a building, they've got curtains, they've got a golden gong, they are near a main road, and there's a Subway, Costa and a pizza place nearby.
They have made it clear they aren't in nearby Nottingham - which was one of the pair's first ports of call as the game got underway.
The DJs travelled to the city and were spotted by listeners - leading listeners to believe they might not be too far away.
Now fans on Twitter have decided the pair are hiding out in Sheffield.
Suzzanna Leeming said: "They're in Sheffield uni arts tower! Its graduation day, end of term. Giant cranes. Busy road, Parkway, Costa, Subway and Pizza Express all together. Big hills. Come on!!!"
Demi Stafford-Graham posted: "Are @grimmers and @gregjames at Sheffield Valley Centertainment? Theres a cinema with velvet curtains, There’s a Pizza Express, Costa and Subway. It’s also near a busy junction and hills...plus they were spotted on a train to Sheffield."
Leah_Groom said: "Near the Moor in #Sheffield - has all the restaurants, is next to the inner city ring road. Lots of construction around there atm, so cranes/lorries feasible. Sheff is built on 7 hills so it's hard NOT to see one & it's close to Notts."
And Dale Vella wrote: "Pretty sure @gregjames and @grimmers are in Sheffield. Probably the Information Commons or one of the other uni buildings. #hideandseek."
The two presenters are taking part in the stunt to celebrate the upcoming permanent swap of their Radio 1 shows.
Greg moves to Breakfast in the Autumn and Nick will take on Drivetime.
They have promised to stay on air until their hiding place is found - which could potentially mean hosting a joint show for the foreseeable future if they are any good at hiding.
Listeners have been asked to track the duo down with the help of clues given out on air.
"We are in a building, don't go looking in a ditch. Don't go into a haunted forest," said Greg.
"The best bet is for everyone to work together to share your suspicions and theories."
Their big game was planned in such secrecy, that even the bosses at Radio 1 were unaware of what was going on.