Geri Horner apologised to fans for leaving the Spice Girls over 20 years ago in an emotional speech on the last night of their tour.
She told fans at Wembley Stadium that it was “so good to be back” after her departure in 1998.
The rest of the group carried on until 2000 before announcing a seven-year hiatus.
Geri, Mel B, Mel C and Emma Bunton took to the stage for the final time on Saturday night after a 13-date UK and European tour.
Ginger Spice told the sold out stadium: “I just want to say I’m sorry. It’s just so good to be back with the girls that I love.”
The girls also brought out their mums for a rendition of hit single Mama.
Adele was in the audience for the tour finale, with the band singing a snippet of her hit single Someone Like You.
Geri posted a picture of her and the songstress hanging out backstage on Instagram, with the caption “finally together.”
Actor Emma Stone attended Friday's gig.
Earlier on Saturday, Geri met groups of fans who had waited to catch a glimpse of her, with one even getting her signature on his arm so he could have it tattooed.
Mel C posted an emotional tribute to her bandmates on Instagram, with a throwback photo of the group in their heyday.
She wrote: “In 1994 five girls answered an advert in The Stage newspaper for a new girl band. 25 years later, those five girls headline Wembley Stadium, for the third night in a row!
“Never in my wildest dreams could I have imagined that all these years later we would be playing to sold out stadiums, performing what I believe to be the best show we’ve ever done.
“It’s an honour and a privilege to share a stage with my fellow Spices, @therealgerihalliwell @officialmelb @emmaleebunton and the gorgeous @victoriabeckham will always be missed (hopefully someday to return)!
“I never forget though, none of this would have been possible without you - the unbelievable fans.
“You have made a very normal girl feel incredibly special and I can never thank you enough for this. I love you all and thank you from the bottom of my heart for allowing me to live this amazing life.”
On Thursday, Mel B described the Spice Girls' concert in London as one of the most important moments of her life.
