Labour mayoral candidate Ken Livingstone has offered his former party rival a job if he is elected.
Mr Livingstone announced today that he would make Oona King his Young People's Champion if he was victorious at next week's vote.
Baroness King stood against him in the contest to select the Labour Party's mayoral candidate in September 2010. The former Bethnal Green and Bow MP, who also worked as a Downing Street adviser to Gordon Brown, offered her unequivocal support to the Livingstone campaign after her defeat.
Baroness King, who lost her parliamentary seat to Repect MP George Galloway in 2005, is the daughter of a Jewish mother and a black father. She was backed in her mayoral bid by historian Simon Schama and private equity millionaire Sir Ronald Cohen.
Baroness King said she was determined not to "let the Tories get away with how they've made things worse for young Londoners".
She said: "I want to do everything I can to help young Londoners by working with Ken as part of a Labour team that makes Londoners better off. Ken's Labour initiatives from reintroducing EMA, supporting for Safe Havens, helping girls in gangs, implementing anti-poverty strategies, pre-apprentice pilots, and cutting fares show exactly how much better off Young Londoners will be with Ken as their mayor."
Mr Livingstone added: "I'm delighted that she's agreed. Oona will form an integral part of a fresh Labour administration at City Hall."