Announced last month, Frank Sinatra: Their Way is being produced by Whizz Kid Entertainment and will pay tribute to the singer’s influence over the last seven decades.
It’ll also offer one act the prize of performing at a special Sinatra centenary concert to be held in 2015.
Armstrong, host of BBC One’s hit show Pointless is a long-time Frank Sinatra aficionado who has recently performed Sinatra classics with his four-piece band. Alexander said: “I am so excited to be celebrating this Sinatra centenary year in such fantastic company.
“We’re going to be throwing the spotlight onto some truly inspirational and dazzling acts from all around the country. I can’t think of a better tribute to the legacy of one of the 20th century’s most iconic figures.”
Humes commented: “After hosting BBC Children in Need this year I am really excited that BBC One has asked me back to present this brand new show celebrating such a brilliant musical legend, Frank Sinatra.”