Apella provides strategic advisory services to help organisations build sustainable performance and value through aligning their purpose, strategy and reputation.
It was formed in April by senior corporate affairs professionals James Acheson-Gray, who resigned as APCO Worldwide's UK chief in November, Jenny Scott and Matt Young. Silverman becomes the fourth founding partner of the firm.
The co-founders have worked for some of the world’s largest organisations, including the Bank of England, BBC, Danaher, Lloyds Banking Group, Lockheed Martin and Santander.
Silverman said: "I am delighted to be joining Apella. The team is outstanding and what they are setting out to achieve is very exciting."
Young said Silverman brings a wealth of experience to help protect and build sustainable reputations for clients in different markets and sectors, and is a significant addition to the Apella team.
"We are a senior team providing insightful, actionable advice based on robust evidence," he added. "Our clients are those seeking strategic insight from those who have proven expertise in building exceptional reputations."