The winner of X Factor's 2008 series turned West End star scored the highest marks of the series so far.
Bruno Tonioli, Darcey Bussell, Shirley Ballas and even Craig Revel Horwood (albeit after some encouragement) got to their feet for after the performance.
Alex and pro partner Gorka Marquez danced the Paso Doble to 'Ven a Bailar by Jennifer Lopez.
The routine won the pair 9s from each of the four judges to win the biggest score of the 2017 run to date.
However it wasn't enough to help the pair top the leaderboard, with this week's marks added to last week's to determine the overall standing.
Alex had a total of 60 points after scoring 24 for her Waltz to place her third on the overall scoreboard.
Meanwhile, Last week's scoreboard leader - and Alex's former X Factor rival - Aston Merrygold also did well again.
He scored 32 points for his Salsa for a total of 63 across his opening two routines.
At the bottom end was Richard Coles and Charlotte Hawkins.
Richard's 'dodgy' American Smooth scored him 17 points - matching last week's score - for a total of 34 points from the first two weeks.
Charlotte meanwhile had a complete "dance disaster" as she and pro partner Brendan Cole danced the Cha Cha to Sugar by Maroon 5, scoring just 12 marks.
The total judges' marks from thepast two weeks will combined with the results from the first public vote.
The two celebrity couples in the bottom two of the overall rankings will find themselves having to dance again in tomorrow night's (Sunday) results show.
Strictly is back Sunday night on BBC One with the results from 7:15PM.