The 51-year-old Ted Lasso actress was due to sing the much-loved carol In The Bleak Midwinter to 1,600 guests including Royal Family members at Westminster Abbey.
Melissa Waddingham, whose family has hunted truffles for generations, claims her 'protege', Ben Sweet, a former marketing consultant, has hijacked her expertise to set up on his own.
The actress, 51, who has been tipped to replace Claudia Winkleman and Tess Daly as a host of Strictly Come Dancing, wore a long burgundy coat to the event.
The 5ft 11in actress claimed that she was turned away from roles due to her model stature, saying the general sentiment was 'you'll be too big on camera'.
Hannah Waddingham showed off her enviable figure as she attended the event that saw Tom Cruise receive a BFI Fellowship. The actress, 50, is starring alongside Tom, 62, in Mission: Impossible.