It looks like the sun... but it isn't.
It's a brand new type of artificial skylight called CoeLux which, for the first time, reproduces the scientific phenomenon that makes the sky appear blue.
CoeLux, which has been shortlisted for the Light Source Innovation of the Year Award at this year's Lux Awards, was developed by Italian scientist Paolo Di Trapani.
It comes closer to recreating a sunlit sky than any lighting product we've seen.
The secret is a solid layer containing nanoparticles that produce Rayleigh scattering - the same process that occurs in the atmosphere, splitting up different wavelengths of light to make the sky appear blue. CoeLux also creates an illusion of depth to make the 'sun' appear to be far above - but the makers are tight-lipped about exactly how that's done.
The innovative skylight has been brought to the UK by Ideaworks, which specialises in technology for high-end interiors in the residential and hospitality markets. The Ideaworks team are hoping to bring (artificial) sunlight to London's new breed of 'iceberg homes' with cavernous basements, and other underground spaces that until now have lacked natural light.
But if you want to install a CoeLux skylight, you'll need to dig deep - in every sense. It requires a one-metre ceiling recess, and will set you back tens of thousands of pounds.
Initial versions don't allow dimming or control of the colour or position of the light source, although the team hope to develop dynamic versions in future.
You can experience CoeLux in action for free at LuxLive on 19 and 20 November at ExCeL London. Head to luxlive.co.uk to register