Geri Halliwell's
ready to spice up her life ... with a new husband!

The former Spice Girls singer announced that she and her Formula 1 racing beau Christian Horner are engaged via Twitter on Tuesday.

"Christian and I are delighted to announce that we are engaged! We're both very happy," she tweeted.

The cute couple went public with their relationship last March, and this will be the first marriage for the red-headed beauty.

Both Geri and Christian have children from their previous relationships -- Halliwell has an 8-year-old daughter, Bluebell, and Horner has a 1-year-old daughter, Olivia.

Congrats to the happy couple -- now, here's to hoping that there's a Spice Girls reunion at the 42-year-old's wedding!

What do you think of Geri's 40-year-old fiance? Sound off below and click "Launch Gallery" above to see even more celebrity wedding and engagement bling and the Spice Girls then and now!