The 38-year-old, who took to the stage on the last night of the London 2012 Games with her bandmates Emma Bunton, Melanie Brown and Geri Halliwell, said it was Bunton who turned to calm her as they made their way to the stadium, reported Femalefirst.
"I was in the taxi with Emma before we started and I nearly just got out of the car. I was so nervous. I felt sick and Emma was so amazing. Honestly, that's how you know a real friend. If it wasn't for her, I would not have been out there," she said.