Mel B performed energetically at the Spice Girls' 30th anniversary concert in London.
Fans packed tightly into the O2 Arena.
Melanie C said the show was heart‑warming.
The night was marred by a reported feud inside the group recently.
The dispute centres on leadership and payments.
The event marks three decades since the group first burst onto the scene.
Later that day Mel B appeared as a stand‑in judge on America’s Got Talent.
A teenage singer took the stage and earned the judge’s golden buzzer right after the final note to cheers.
The buzzer sent the act immediately to the live shows.
Cowell pressed it instantly.
Mel B said the singer showed great confidence.