The singer, who was a judge on television's The Voice and has appeared in a number of West End shows, will be taking to the stage at Keel Square where she will join The Right Worshipful Mayor of Sunderland, Councillor Doris MacKnight, for the switch on.
The performance - which will take place at 5.30pm - is one of a whole host of events planned for the city's Christmas festivities.
A range of community entertainment will begin from 4.30pm, supporting the NSPCC and its Light Up Christmas for Children Campaign.
The Sky Cinema Bus will also be at Keel Square throughout the day, showing a range of Disney short films for all the family.
Street food stalls offering everything from authentic pizzas to fish and chips will also be found at High Street West.
Also taking place on the same evening as the switch on at Keel Square is a spectacular live performance to celebrate the launch of The Fire Station as a new arts venue.
The performance, named Fireflight, will feature more than 100 local people and has been created by acclaimed outdoor theatre company Periplum and will be followed by a fire show at 6.45pm.
The performance is a ticketed event, with details on how to apply for tickets available from the Cultural Spring website, two weeks prior.
"We have been working all year on ensuring that Christmas in Sunderland is going to be absolutely fantastic," said Sharon Appleby, Head of Business Operations at the BID.
"We have worked closely with Sunderland City Council and a number of other partners to bring together what promises to be a truly amazing start to the festive season.
"We're also very grateful to Sun FM for securing a star of the calibre of Pixie Lott to get the event underway."
Cllr John Kelly, Portfolio Holder for Public Health, Wellness and Culture, said: "Attending the Christmas light switch on is an annual tradition for many families in the city, and this year's event looks impressive, with the confirmation of Pixie Lott's performance.
"The Fire Station will bring another city centre venue back to life, with a whole programme of cultural activities, starting with an exciting launch on the 23rd.
"Working in partnership with other organisations in the city is key to the ongoing success of our events and attractions, and we'd encourage local people and visitors to make the most of our Christmas activities, which will be bigger and better than ever."
All City Council car parks, including Livingstone Road and St Mary's, are free after 3pm on Thursdays.