The ladies were voted off in the celebrity dance show's semi-final.
Their demise means that Australian entertainer Jason Donovan, McFly drummer Harry Judd and Waterloo Road star Chelsee Healey are in the line-up for the final in Blackpool next week.
One Show presenter Alex and Australian actress, model and singer Holly came up short against sizzling performances by Chelsee and Jason, who both scored the first perfect 40 scores of the series.
Harry also chalked up two 39 scores as the dancers performed two numbers each, leaving Alex and Holly at the bottom of the scoreboard ahead of the audience's vote.
Gracious in defeat, Alex said that apart from occasionally mistaking left and right while dancing, her time on the show had been "brilliant".
She said: "I've had an incredible time, and when I'm old and grey I'll look back at these three months and I'll think 'that was a brilliant time'."
Alex's dancing partner James Jordan praised her for her dedication, saying: "If there was a trophy for the most improved dancer, for sure you would have won that trophy.
"I would like to say whoever gets to work with you in the future is very, very lucky. You have been absolutely brilliant to work with, it has been an honour."
Holly also took the bad news on the chin, saying: "I'm just proud that we've been part of the most successful Strictly.
"The British public has been incredible, this is much further than we ever thought we could ever imagine."
Strictly Come Dancing's live grand final will be broadcast on BBC One next weekend from Blackpool Tower Ballroom.