In what the online TV service from Arqiva is claiming as "a landmark first for the UK," consumers will have the opportunity to choose from three separate ads by an individual brand before watching a programme online.
It is designed to stimulate viewers' engagement by getting them to choose the ad they wish to watch, a process found to improve brand recall and increase purchase intent.
SeeSaw programmes from BBC Worldwide and independent producers are hosting the service from today.
Ad Selector's arrival follows the SeeSaw service launching in the US at the start of the year. A range of other VoD services in the US host similar services, including Hulu and CBS.com.
Ben Williams, head of advertising at SeeSaw, said: "The Ad Selector puts the user in control of the advertising experience and therefore increases their engagement and purchase intent.
"Our vision is to create a unique environment for advertisers to reach their audience through innovative methods, and today's announcement is the first step towards this, with more initiatives in the pipeline."
The service has been launched in partnership with interactive video company Brainient. The production process is said to be "straight forward," combining traditional video formats with flash-based overlays.
Williams predicts there will be an incremental change in the type of advertising hosted on the service in 2011. Liking it to the development of online display ads 10 years ago, he expects creative agencies to increasingly think about innovative VoD content at the start of the production chain, when relevant for the client.
He said: "The next evolution will be about enhancing, not replacing, repurposed TV assets and content."
SeeSaw has attracted a wide range of advertisers, including blue chip giants Microsoft, Coca-Cola, Heinz, Ikea, O2 and Sainsbury’s, since it launched in the UK on 17 February.