Publicis Groupe, awaiting approval for a merger with Omnicom Group, isn't slowing its fast-paced acquisitions drive. The company confirmed today that it is on the verge of buying of a majority stake in London-based Walker Media, which is 75% owned by M&C Saatchi.

The proposed deal -- which comes as Publicis and Omnicom push back the target date for their merger from "first quarter" to "first half" of next year -- is thought to be worth $55 million and values Walker Media at $75 million. It would indirectly link M&C Saatchi with Publicis Groupe's Saatchi & Saatchi once again, 18 years after Maurice and Charles Saatchi broke away acrimoniously from the agency the brothers founded in 1970. M&C Saatchi will retain a significant stake in Walker Media, alongside Publicis Groupe's majority stake.

Walker Media, founded in 1998 and run by chairman and co-founder Phil Georgiadis with CEO Simon Davis, has a strong pedigree in the U.K., but has few clients in common with M&C Saatchi. Its clients include Fox, KFC, Taco Bell, Sony Entertainment, Mandarin Oriental, Marks & Spencer, and the National Geographic Channel.

The well-regarded media agency could be used to boost ZenithOptimedia, which is currently without a U.K. leader following the departure of CEO Tim Hipperson, who quit after the agency lost the $215 million L'Oreal account to WPP's Maxus last month. There is Zenith DNA at Walker Media -- founder Christine Walker, who stepped down in 2007, was formerly CEO at Zenith Media Services.

Publicis issued a statement on Thursday after news of the pending deal leaked in London. In the statement, Publicis Groupe confirmed that it is "in discussions with M&C Saatchi in relation to Walker Media, which may involve the purchase of a significant part of that business. There can be no certainty that an agreement will be reached and a further announcement will be made in due course."

If Publicis goes ahead with the Walker deal, a combined Publicis and Omnicom would have more than ten separate media brands in the U.K., suggesting that media consolidation might be a priority for what is potentially the world's number one advertising group.

Publicis Groupe last significant deal in London was in September, with the $20 million purchase of Poke, which was 50% owned by Mother.

M&C Saatchi and Walker Media did not respond to requests for comment.