Mark Zuckerberg has built a glowing wooden box to help his wife Priscilla sleep better at night as she cares for their two children.

The Facebook CEO, 34, took to Instagram to inform followers of his latest invention and the reasoning behind it.

The 'sleep box' emits a very faint light between 6 am and 7 am, when their daughters Max and August usually wake up.

Mark Zuckerberg, (left), has built a glowing wooden box to help his wife Priscilla Chan, (right), sleep better at night as she cares for their two children

The 'sleep box', (pictured), emits a very faint light between 6 am and 7 am, when their daughters Maxima and August usually wake up

The box doesn’t show the time as that would cause stress for his wife Dr Priscilla Chan, 33, and disrupt her sleep, the billionaire tech entrepreneur said in an Instagram post.

He explained: 'Since it doesn't show the time, if she wakes up in the middle of the night, she knows to just go back to sleep without having to worry about what time it is.

'So far this has worked better than I expected and she can now sleep through the night.'

The post garnered a number of comments online. Former Facebook manager and angel investor Dave Morin called the device, 'Genius.'

Zuckerberg wrote that those in his social circle have been supportive of the idea.

He said: 'A bunch of my friends have told me they'd want something like this, so I'm putting this out there in case another entrepreneur wants to run with this and build sleep boxes for more people!.'

Chan and Zuckerberg married in their Palo Alto backyard in 2012 after dating for nine years. Chan, 33, is an American philanthropist and pediatrician who was born to immigrant parents from China.

The couple welcomed their first child Max in 2015 and their second daughter August was born two years later in August 2017

The Facebook CEO took to Instagram to inform followers of his latest invention

She was born and raised in Massachusetts and grew up speaking both Cantonese and English. She then attended Harvard University where she met and began dating Zuckerberg.

Their first child, Maxima Chan Zuckerberg or 'Max', was born on November 30, 2015. In August 2017, they announced the birth of their second child called August.

In October 2018, the notoriously private couple opened up about their ambitious joint venture, the Chan Zuckerberg Initiative, which focuses on advancing human potential and promoting equal opportunity.

Since the couple joined forces for CZI, they say it is important to stay organized and set aside time for conversations about business aspects versus family talk time.

Chan and Zuckerberg married in their Palo Alto backyard in 2012 after dating for nine years

'We used to go out to dinner to talk about CZI one night a week,' Zuckerberg said at the time, 'but that felt weird over time, because we also go out on dates.

'I just think psychologically, you want to have different places. So now we carve off time, like our one-on-ones.

'And then when we're at the kitchen table with our kids, it's not like we're not talking about what's going on in our lives—that's weird too, you're not going to turn things off that are important and emotional—but we try not to go through logistics and details and stuff like that.'

In October 2018, the notoriously private couple opened up about their ambitious joint venture, the Chan Zuckerberg Initiative, which focuses on advancing human potential

Chan claimed she actually turns to her children's pediatrician for parenting advice, despite being one herself.

'I asked our pediatrician, can we talk about work in front of our children,' Chan said.

'We want them to be exposed to the types of issues [at CZI], but I don't want them feeling like there's a lot of disorder in the world.

'And the pediatrician's advice was, it's fine to have those conversations, just take it to its logical conclusion so they see that conflict gets resolved.'

CZI is one of the best funded start-ups to date, with $45billion pledged in that initial announcement.

Chan is the leader and oversees the annual budget which ranges around of $700-800 million yearly. One of CZI's ambitious goals is to help prevent, cure or manage all disease over the next century.