Sorrell, who is chairman of the London Design Festival and co-chairman of The Sorrell Foundation, recently authored the Creative Island book for UK Trade & Investment.
His new role will see him promoting British business overseas, with a particular focus on small and medium-sized enterprises.
Sorrell has been appointed alongside UKTI life sciences board chairman Chris Brinsmead, Lord Ara Darzi, IBM Europe chairman Larry Hirst, Lady Barbara Judge and Professor Julia King.
They join a group of 18 existing Business Ambassadors, including Sir Terence Conran and Lord Rogers.
Sorrell says, ‘I have worked in the creative industries sector all my life and am constantly impressed by the extraordinary level of creative talent that continues to emerge from these shores.’