The film follows the story of several children, including some who have suffered neglect, and includes the message: "A child's past should never define their future."
Barnardo's chief executive Javed Khan said the campaign, which first launched in 2016, was designed to focus on the transformative effect that believing in children has on their lives.
The second phase includes research for Barnardo's by YouGov that reveals 88 per cent of children say they need to be loved to have a happy childhood.
The research, which surveyed over 1,110 children in the UK, also shows 79 per cent think having a parent or guardian that encourages or believes in them is important for a positive future.
Khan said: "We hope people who see the ad will be inspired to donate to Barnardo's so we can carry out our vital work. We know that when people believe in children, they start to believe in themselves and incredible things can happen."
The campaign film launched on TV last Friday (24 November), and will appear across Barnardo's' social channels throughout the festive period.