She said thank you in a special three-minute speech to the nation which was shown on all TV and radio stations.
'Overwhelming'
The Queen said she was really moved and overwhelmed by the number of people who have paid tribute to her mother.
Just before her speech, the Queen Mother's grandsons, princes Charles, Andrew, and Edward, and Viscount Linley stood silently for 20 minutes with heads bowed at the four corners of her coffin.
Prince Charles stands in vigil
People filed past the coffin in silence.
Prince William and Harry were also there to support their dad and pay their own respects.
Over 100,000 people have already queued for hours to pay their respects inside Westminster.
And a total of 500,000 are expected to see the coffin before the funeral.
Funeral plans
Fact File
Funeral timetable
0600 Westminster Hall closes
1030 Main congregation seated
1118 Royal procession along abbey's centre aisle
1130 Service begins
1225 Service ends
1235 Cars leave for Windsor in slow procession
1300 Coffin goes to St George's Chapel, Windsor
She also talked of the funeral which will be held on Tuesday at 1130.
She said: "I hope that sadness will blend with a wider sense of thanksgiving."
The funeral will be attended by 2,100 guests and people outside will hear the service on loud speakers along The Mall.
People are already camping out beside Westminster Abbey to watch the funeral procession.
Hear story!
The funeral plans: what happens when?
The Queen Mother: your tributes
I watched the royal procession
