Signet is increasing the number of regions where its UK advertising campaigns are aired, following the appointment of agency McCann-Erickson.
The agency will devise separate campaigns for both Ernest Jones and H Samuel.
Last year's campaigns ran in the North and the Midlands for H Samuel and Greater London for Ernest Jones.
Signet group chief executive Terry Burman said ads would be aired later this year in more areas, but no decision had yet been made on exactly which.
UK like-for-like sales at Signet jumped 5.5 per cent in the year to January 31. Sales were boosted by a continuing push into diamond jewellery at both fascias.
Diamond sales grew 50 per cent faster than the UK diamond market, said Burman.
UK sales increased by 5.8 per cent to£501 million and group sales rose by 1 per cent - 7 per cent at constant exchange rates - to£1.62 billion.