In the mid-1950s, despite appearances in London's West End and a number of recordings for MGM, Ambrose, in common with other bandleaders, was struggling because rock and roll had arrived. He was forced to start performing in small clubs with casual musicians, and his financial position deteriorated catastrophically. His situation was saved, however, by his discovery of the singer Kathy Kirby, whom he heard singing at the age of 16 at the Ilford Palais. He started a long personal relationship with Kirby and promoted her career.