A radiant and very pregnant Jessica Alba braved the night's slime.

Despite the forecast of torrential slime, Hollywood's A-list showed up in droves for the 21st Annual Nickelodeon Kids' Choice Awards in L.A. on Saturday night. Dressed in a too-tight, green, get-up, JACK BLACK hosted the festivities, which saw MILEY CYRUS win big and rock the roof, HEIDI KLUM get shot out of a mock cannon, and HARRISON FORD and ORLANDO BLOOM get the sliming of their lives.

Other stars to make cameos included WILL SMITH, JANET JACKSON, USHER, JESSICA ALBA, EDDIE MURPHY, HARRISON FORD, SHIA LABEOUF, PETE WENTZ and ASHLEE SIMPSON, CAMERON DIAZ, ASHTON KUTCHER, STEVE CARELL and reigning "American Idol" champ JORDIN SPARKS.

The evening's banner moment came when award-presenters Harrison Ford and Shia LaBeouf -- the dynamic duo set to star in 'Indiana Jones and the Kingdom of the Crystal Skull' -- recreated an unforgettable scene from Indy's first flick: Taking center stage, Harrison approached a pillar and gingerly plucked off an award, which he quickly swapped with a pint-sized orange blimp -- the coast looked clear until an orb above his head exploded and doused him with slime!