The incoming First Lady wore a pale blue cashmere ensemble.
The candlelight dinner will be held tonight at Union Station.
She replaces Judy Collinson; fashion director Julie Gilhart also departs.
Stella McCartney and her husband, Alasdhair Willis, have welcomed the latest addition to their family — a baby girl.
Group says settlement reached on Unilever acquisition.
The retailer and holding company I.T Limited will be 50-50 partners.