The 43-year-old singer is reuniting with the the pair and Mel C (Melanie C) for a U.K. tour this summer, and their comeback was hit by controversy last month when Mel claimed she had been intimate with Geri in a pre-recorded interview with British newsman Piers Morgan.
Ginger Spice Geri denied the fling and now Emma is unsure what to believe, as she never heard anything about any relationship at the time.
She told U.K. radio host Chris Evans: "It's the first I've heard of it! With Mel B, you have to take everything with a pinch of salt. She's great fun."
Emma confessed she had yet to see the interview, which will air as part of the latest series of Piers Morgan's "Life Stories" later this year, and joked that she felt "left out" as Mel C was in the audience.
Mel, full name Melanie Brown, is reported to have nodded when Piers asked her if she had slept with her bandmate and then added: "She's going to hate me for this because she is all posh in her country house and her husband, but it's a fact. It just happened and we just giggled at it and that was it. We were best friends. Have you ever done that?".
Geri Halliwell, who is now married to Christian Horner, subsequently issued a statement through a representative denying the story and calling reports "hurtful" to her family.
"Geri loves the Spice Girls: Emma, Melanie, Melanie and Victoria (Beckham)," her denial read. "She would like (the fans) to know that what has been reported recently is simply not true and has been very hurtful to her family. Moving forward, Geri can't wait to see the girls and all the fans on the tour, have an amazing time with everyone, and make some new memories."
She and Christian are parents to two-year-old son, Montague, and Geri also has a 12-year-old daughter, Bluebell Madonna, from a past relationship with filmmaker Sacha Gervasi.