The night service is the most expensive for ChildLine to run because it uses professional counsellors.
The charity is using a 60-second viral video on a specially designed website called wehearscaredpeople. com, to spread an urgent plea for donations by email. The viral campaign is running in conjunction with the charity's conventional night service appeal.
The email, which shows emotional video clips of child actors using the night service, was first released to 200 ChildLine staff and volunteers.
In its first two weeks, the email has been 'virally' forwarded to more than 5,000 people. This figure is expected to increase as the campaign becomes better known.
The idea has been in the pipeline since February and, coincidentally, was ready for release with the night service appeal, set up last month in a bid to raise £1m that would restock the charity's empty reserves.
International appeals for the tsunami disaster, Sudan and Niger have left smaller charities such as ChildLine struggling for funding, according to Matt Parkes, head of marketing.
Donations from its Christmas appeal plummeted from 50 responses a day before the tsunami to just one or two a day, and the response to April's direct mailout was a third down on last year's.
Parkes said that although it was right that these "crucial" appeals received funding, smaller domestic charities must not be forgotten.
Although comparatively few children call ChildLine in the early hours of the morning, those who do are often in the most urgent need of help.
As the fundraising viral video is a first, the charity is not putting any figures on how much it hopes to raise.
It cost the charity nothing because it was made pro bono by video producers at advertising agency Quiet Storm and website designers at Frank's Ice Store.
Parkes said: "It is a critical time, and there is no way we could have produced this without the generosity of all those involved."
The charity is now in discussions with media companies to try to get the short film into cinemas and onto television.