Freuds has been working on a pro bono basis and has been responsible for all areas of PR for the charity single, from media management to a press conference last Monday.
An agency spokesman said it was called in on the project through its "existing connections". Freuds founder Matthew Freud is close to Band Aid founder Bob Geldof and the agency worked on Live 8 in 2005 and Live Earth in 2007.
The agency’s previous work on Live 8 focused on putting pressure on governments and changing public opinion, whereas the main objective with Band Aid 30 is to raise funds.
Freuds looked at multiple ways to raise money, including driving pre-sale downloads and promoting competitions with text-based donations.
When looking at press opportunities, the company focused on what would garner the most funds. No official images were released so that publications had to pay for images if they wanted to run the story.
The song features vocals from One Direction, Chris Martin and Ellie Goulding, as well as Bono, who sang on the original 1984 recording.
As well as established singers, it features YouTube stars Zoella Sugg and Alfie Deyes in an attempt to broaden the potential audience for the appeal.
The charity single was broadcast for the first time on Sunday night on ITV’s 'X Factor'. It is available to download from iTunes and will be released on CD in three weeks' time.