There's a feud among the Spice Girls ever since "Scary Spice" Mel B revealed she once had sex with "Ginger Spice" Geri Horner, a new report claims.

An insider claims that Horner hasn't responded to messages from Mel B ever since she confessed during an interview with Piers Morgan that the two women slept together, and it's causing drama among the rest of the Spice Girls — who are embarking on a reunion world tour later this year.

That may be because Mel B and Horner's relationship extended beyond a one-night stand.

MEL B EXPLAINS COMMENTS ABOUT SEXUAL ENCOUNTER WITH GERI 'GINGER SPICE' HORNER

Insiders told The Daily Mail that Horner and openly bisexual Mel B were actually in a romantic relationship for a year.

"It was in the very early days of the Spice Girls and their relationship lasted far longer than one night – it was at least 12 months. They deeply bought into the whole Girl Power phenomenon — they wanted to lead it," the source said. "They felt what better way was there to do that than for girls to enjoy one another?"

MEL B GETTING TREATMENT FOR PTSD, SEX ADDICTION

Geri Halliwell and Mel B (Ginger Spice and Scary Spice) of the Spice Girls had sex, are bisexual LONDON - JANUARY 04: *** EXCLUSIVE ACCESS *** Melanie Brown and Geri Halliwell of the Spice Girls perform on stage during The Return of Spice Girls World Tour at the O2 Arena on January 04, 2008 in London, England. (Photo by MJ Kim/Spice Girls LLP via Getty Images)

Geri Halliwell and Mel B (Ginger Spice and Scary Spice) of the Spice Girls (Getty)

Horner and Mel B reportedly fell in "lust at first sight" when they first met at ages 21 and 18, respectively.

Horner has been married to Christian Horner since 2015.

HEIDI KLUM 'CAN'T WAIT' TO READ MEL B'S TELL-ALL BOOK

She previously said of her sexual experiences with other women, "I don’t mind boobs but the other bit is not my cup of tea. I realised I was not a lesbian. It is part of experimenting."

Meanwhile, Melanie "Sporty Spice" Chisholm (Mel C) was in the audience during the interview and reportedly mortified at the revelation.

“The girls are due to start rehearsals next month, but the whole thing is in chaos. She’s not replied to any of her messages and is properly sulking," a source told The Sun. “Mel C is unhappy too as she felt put on the spot, and publicly humiliated. She simply doesn’t want the drama of it all.”

Mel B and Geri Halliwell (Scary and Ginger) of the Spice Girls photographed backstage at the Brit Awards in February 1997.; (Photo by Ray Burmiston/Photoshot/Getty Images)

Mel B and Geri Halliwell (Scary and Ginger) of the Spice Girls photographed backstage at the Brit Awards in February 1997. (Getty)

MEL B SAYS EDDIE MURPHY WILL ALWAYS BE THE 'GREAT LOVE' OF HER LIFE

In the same interview, Mel B reportedly called Victoria "Posh Spice" Beckham a "b—h," further irking the rest of the Spice Girls.

“Victoria doesn’t want anything to do with this reunion malarkey," the source said. "It’s exactly this sort of nonsense she wanted no part of."

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The Spice Girls reunion tour kicks off on May 24 in Dublin, Ireland.