It's a sleepover that's been 200 million years in the making.
Luckily though, dinosaur fans don't have to wait very much longer to spend an entire evening with their favourite creatures.
National Museum Cardiff will this weekend hold a prehistoric themed lock-in with some of its most awesome residents - the life-size skeletons of beasts which walked the Earth before time began .
Visitors will be able to embark on a torch lit tour to explore Wales as it was all those millennia ago, as well as meeting the likes of Dippy, the iconic Diplodocus who is there on loan from London's Natural History Museum.
Cast from a near complete skeleton discovered in Wyoming, America in 1898, Dippy is made up of 292 bones and is an impressive 21.3 metres long, 4.3 metres wide and 4.25 metres high.
Aimed at those aged six to 12 - and accompanying adults - the event will also feature craft workshops, the chance to watch dinosaur eggs hatch and an opportunity to take in a film in the museum's grand theatre, before camping out under the venue's dome.
Snacks and drinks are included, with guests also able to visit the Evolution of Wales gallery after breakfast the following morning.
A huge hit in past years, the event runs from 5.30pm on Saturday, January 25 to 9am on Sunday, January 26 .
Click here for tickets.
