Tony Illsley, who is currently president of Walkers Snack Foods, should be confirmed in the post early next month. Mr Illsley, in his early 40s, has been running Walkers in the UK for the past three years.
His appointment follows an extensive search by Telewest following the departure of former chief executive Stephen Davidson in April.
Telewest had been looking to appoint a British executive with marketing experience to raise the company's appeal.
He will be joining Telewest just as the cable sector is coming back into vogue after a lengthy slump.
Shares in all the cable operators have risen sharply on the back of rapid consolidation in the industry and growing optimism about their ability to combine television, telephone and high-speed Internet access services. Telewest shares have more than doubled in the past few months alone and the company is now poised to join the FTSE 100 index.
Nevertheless, Mr Illsley will still have a lot to do. His first job will be oversee the integration of General Cable, the rival operator which Telewest bought earlier this year.
The company is also still struggling to dispel its public image of shoddy customer service. Recent results showed that Telewest's market penetration in both telephony and television is almost static while churn rates remain high.
While Mr Illsley should bring much-need marketing acumen to Telewest, his lack of industry experience may prove a problem. His appointment may be short term.
Analysts believe that further consolidation could leave the UK with just one cable operator instead of the current three.