The 'Hold It Against Me' hitmaker - who has hit the country on the latest leg of her Femme Fatale tour - asked for a picture of the late royal, who died in 1997, in addition to portions of fish and chips and 100 figs and prunes.
A source said: "Britney adores the Monarchy, Diana was in many ways her inspiration. Also, she doesn't count calories when she's in Britain."
Toothpaste and McDonald's cheeseburgers minus the bread rolls were also part of her rider before she performed at London's The O2 last night (27.10.11).
Britney has previously revealed she would love to perform For Diana's son Prince William and his wife the Duchess of Cambridge - who married in a glittering ceremony at London's Westminster Abbey on April 29 - should they wish to come and see while she is in the UK.
She said: "I'm sure they're very, very busy, but if they could Squeeze it in that would be amazing.
"It would be amazing if they came to one of my concerts. That would be really crazy and cool. I think they're a beautiful couple."