One of the biggest bands of the 90s are reuniting on stage on Friday.
Baby Spice told Heart Breakfast: "It's so much fun, being back on stage with the girls. Literally, we giggle to ourselves and of course we make mistakes in the dress rehearsals."
And she said: "I've remembered all the words and I'm just getting to grips with the choreography, so I think we're there."
The Spice Girls will reunite on stage for the first time in seven years when they perform in Dublin.
Victoria Beckham will not be joining Melanie Brown, Melanie Chisholm, Geri Horner and Bunton.
But Bunton said she "really hopes" that Posh Spice will see her former bandmates at some point on the tour.
And she added: "She's emailed me this morning so it's lovely - I hope she comes along."
Bunton said she had "butterflies in my tummy" and that she was wary about putting on her trademark, platform Buffalo boots "cos I've fallen over in them a few times".
She said the band were getting on, but quipped: "It's the first night tonight, so who knows what's going to happen."
The band had to deny rumours of a rift in April following Brown's claims that she had a one-night stand with Horner in the Spice Girls' heyday.
The Spice World Tour was announced last November and will be the first time the group has performed since the closing ceremony of the London Olympics in 2012.
Horner shared images of the set-up for the performance, which features an imposing Spice World sculpture and large screens on each side of the stage.
After Friday's show at Croke Park the Spice Girls will head to Cardiff's Principality Stadium (May 27), the Etihad Stadium in Manchester (May 29 to June 1), Coventry Ricoh Arena (June 3-4), Sunderland Stadium Of Light (June 6), Edinburgh BT Murrayfield Stadium (June 8), Bristol Ashton Gate Stadium (June 10) and London's Wembley Stadium (June 13-15).