"History is being made," Howard Draft, who will lead the combined operation, boasts. Meanwhile, Michael Roth, the chairman of the newly named Draft FCB group's parent, Interpublic, says it will be "highly responsive to the new realities transforming the consumer and media landscape".
For once, some - though not all - of the hype may match the reality. The complementary skills of the two networks raise the prospect of a formidable marketing powerhouse operating out of Chicago. What is more, conflict problems look to be minimal and, in Draft, the combined operation has a leader with an outstanding reputation.
The big challenge will be banishing doubts among clients that Draft FCB is more than just a self-serving exercise on IPG's part. FCB is widely acknowledged to have struggled in recent years, having lost the Kimberly-Clark, Samsung and DaimlerChrysler accounts. Apart from SC Johnson, there is little other "cement' binding the network together.
Moreover, the radical stripping out and restructuring carried out by Steve Blamer (who is quitting after just nine months as FCB's global chief executive) has not yet had time to prove its worth.
Whether the merger will make for a healthier bottom line or not is an open question. FCB and Draft are substantial operations in the US, but remain weak beyond their home market. It is hard to see how FCB London will benefit.
Much may depend on how well internal issues are dealt with. Draft is known for his wariness of creative agencies. Also, the fact the Draft name comes first leaves no doubt about who is in the driving seat. Stopping demoralised FCB staffers from feeling like poor relations will be difficult.
Nor should anybody forget the cautionary tale of The Partnership - IPG lumped together the newly acquired FCB with Draft and a collection of its other specialists.
Little more than three years later, The Partnership was quietly killed off, having failed to find a clear management structure.
Have lessons been learned? We are about to see.