In late January, Mel B suggested that the band could reunite for the Queen's Diamond Jubilee.
However, although Victoria Beckham has reportedly refused to be a part of the reunion, with a source claiming that she is too busy with her family, Halliwell has insisted that it should not be ruled out just yet.
"We did get the offer and it is exciting," Halliwell told the Sunday Mirror. "Obviously we are a band and it's a collective decision that has to be made as a band.
"We need to all be in the same place with it and we have to take into account all of our lives.
"We wouldn't do it without all five of us. I do feel it's an incredible honour and privilege," she added. "Performing at Buckingham Palace for the Queen - it doesn't get bigger than that."
The singer recently revealed that she is nearly ready to release her new album.