The musician's daughters lead a host of huge names as they arrived at the London studios today
Pixie and Fifi Geldof lead the star-studded line-up for the Band Aid 30 recording day today, to support their dad on his big project.
The two sisters showed off their usual out-there style as they briefly posed for fans outside, before heading in to help work on the collaboration.
Pixie arrived with best pal and Radio 1 DJ Nick Grimshaw this morning, along with sister Fifi, and they remained inside all day.
Bono, Ed Sheeran, One Direction and Sam Smith joined several other big names from the world of music, including Sinead O'Connor, Ellie Goulding and Coldplay's Chris Martin, to contribute to a recording of Do They Know It's Christmas? today.
It's unclear if Pixie and Fifi will star in the song too, or if they were simply there to offer support.
Both appeared in good spirits outside, and were undoubtedly moved to see their father's success.
Emeli Sande has revealed Sir Bob gave the group a moving speech before they began recording the new single.
"Bob gave a really touching speech before we started singing so I think that really got everybody in the mind- frame that we needed to be in to remind us it's fun but we're here for a really serious reason," she said.
She added: "It was him expressing how passionate he was about this cause and how it's so unnecessary that so many people should be dying."
The 27-year-old said the contributors "sounded like a really powerful choir" and revealed it took about five takes to record the chorus.
The lyrics to the original song have been changed to reflect the Ebola crisis in Africa, with money raised going towards charities helping sufferers.
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