For last week, the agency's atrium was transformed into a stage for the blonde opera sensations The Opera Babes.
The great and the good of M&C's client list could be seen grinning alongside Lord Saatchi with unrestrained glee as the attractive, slim duo trilled their way through their arias to the captivated audience.
Still, never one to miss an opportunity, M&C engineered a shameless commercial hijacking of the corporate function with a bit of old-fashioned product placement for their clients' benefit.
For how should the Babes open the show but by singing while suggestively swigging from ... cans of Foster's. They went on to sing The Flower Duet from Delibe's Lakme - better known as British Airways' theme tune - before the pianist Harry took the audience through his own rendition of the music from NatWest's advertising.
It had all been stage-managed with the ruthlessly watertight precision you'd expect from an outfit such as M&C, until the girls' emotive encore.
For what tune should they choose for the grand finale? None other than, er, You'll Never Walk Alone, Liverpool FC's anthem - doubtless a rather nasty surprise for lifelong Arsenal fan David Kershaw.