The X Factor judge, dressed in wide leg black trousers and a corset, took to the stage after news of Nelson's death broke and performed a rendition of 'This Little Light Of Mine'.
Nicole was presented with the Best TV Personality gong and sang her homage as she collected her award at the Victoria & Albert Museum in London.
The former Pussycat Doll also told the audience an anecdote about a time she sung for Mandela and he jokingly asked if she knew anything else once she had finished.
Nicole looked stunning on the night in her all-black outfit. She wore her long dark hair in a messy up 'do and added a pop of colour with a red lipstick.
Later, Nicole took to Twitter and again paid tribute to Mandela, who passed away in South Africa last night aged 95.
Sharing a photograph of the inspirational icon, she commented: "God Bless @NelsonMandela Tears stream as it was an honour to have known u. U were truly exceptional & an inspiration."
Meanwhile, it was a sombre night elsewhere in London. Prince William and Kate Middleton were at the premiere of new film Mandela: Long Road To Freedom, which is about Nelson Mandela's life, when they were told the sad news.