Peter Andre, 42, shared a photo of himself and his 24-year-old fiancée standing outside that famous black front door yesterday.
He teased: "It's not everyday...
"Fantastic eve. Can't wait to tell you about it Thursday!"
And now, finally, we've learned what he and Emily MacDonagh were up to.
They, alongside Rochelle Humes, Kirstie Allsopp, Charlotte Hawkins, Sara Cox and Donna Air, were there to support the launch of ‘Cancer Research UK Kids & Teens’.
The private reception, hosted by Samantha Cameron, saw the celebs meet with twenty children and teenagers and their families who have been affected by cancer - and it's clear to see from the pictures that the little ones loved meeting Pete and the gang.
Speaking at the reception, Harpal Kumar, Cancer Research UK’s chief executive, said: “Every day more than four children and more than six teenagers and young adults in the UK are diagnosed with cancer.
"While more children are now surviving than ever before there is still much more work to be done. Every child who loses their life to cancer is one too many.
"We need to ensure that no one’s life is cut short from this terrible disease and that those who survive don’t have to live with debilitating side effects."
They continued: “Money raised by ‘Cancer Research UK Kids & Teens’ will be wholly dedicated to research into cancers affecting children, teenagers and young adults, enabling us to better understand these cancers and find kinder treatments and cures.
"In the next 5-10 years Cancer Research UK hopes to double the amount it spends on these cancers.”
The launch coincides with the release of new figures that show cancer deaths in children and young people have fallen by 58 per cent in the past 40 years.
Despite this, cancer remains the biggest killer of children and young people in the UK, with around 550 young lives lost to the disease every year.
If you, like Peter and Emily, want to support Cancer Research UK Kids & Teens, text KIDS3 to 70200 to donate £3.
For more information about the campaign visit cruk.org/kidsandteens