Nikki Bella just gave Indianapolis a huge surprise ... officially making her return to WWE at the "Royal Rumble."

One half of the Bella Twins made her appearance minutes ago ... entering the women's match at the number 30 spot -- with the crowd going nuts when her theme song hit the loudspeakers.

Bella was decked in an all-red two-piece outfit and ball cap ... with her signature "Fearless" logo etched across her chest.

She proved there's no ring rust ... as she even did some push-ups amid all the action. Nikki's fun didn't last too long, though -- she was the 27th wrestler eliminated after Nia Jax forced her out of the squared circle.

Charlotte Flair ended up winning it all ... punching her ticket to WrestleMania in Las Vegas.

Last week, we reported the 41-year-old and WWE started talking about a potential return following her appearance at "Monday Night Raw" a few weeks ago in L.A., which had everyone in attendance -- as well as social media -- in a frenzy.

The match marked her first appearance in the ring since 2022, which also came at the Royal Rumble.

Whether this was a one-off thing or not remains to be seen ... but regardless, fans were hyped to see her back in action following a whirlwind 2024 -- in which she got divorced from her husband following an alleged domestic dispute.