ChildLine's 'Got Talent Ball' will take place at the Savoy Hotel in London on October 21 and will feature the sale of the iconic angel wing-designed chair, as well as appearances from reality TV stars.
Britain's Got Talent's Stavros Flatley, Kieran Gaffney and Twist & Pulse are lined up to provide entertainment to the guests.
NSPCC fundraising manager Rachel Swithinbank said: "We're hoping an ultimate fan will bid lots of money for the last ever Big Brother Diary [Room] chair, helping to raise vital funds for ChildLine.
"All money raised from the event will go towards expanding the helpline and developing ChildLine's online service."
Other items for sale at the auction include a signed Susan Boyle commemorative disc and a trip to the Home and Away set in Australia.
The evening, sponsored by First Direct, is expected to raise over £200,000 for ChildLine.