The Countdown presenter will take to the floor with her partner Pasha Kovalev for the first time this series, dancing a waltz to When I Need You by Luther Vandross.
"Woken up really early, heart is racing, palms are sweaty…it's game day!!" Tweeted an anxious Rachel. "Thanks for messages of support they really help. 12 hours to go! #SCD."
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"On my way to Elstree for hours of Strictly beautifying," she added, who married her university sweetheart last year. "Yesterday's dances were amazing, hopefully Team Saturday can match them! EXCITED! #SCD."
Oxford maths graduate Rachel also thanked her Countdown colleague and Apprentice star Nick Hewer for his encouragement.
"Thanks to the lovely @Nick_Hewer for coming to support me at Strictly yesterday," wrote Rachel. "His badgering & @TheBrendan_Cole got me here - thanks boys!"
"Enjoy yourself tonight R!" Replied Brendan on Twitter. "You're gonna love it."
In the run up to her Strictly debut Rachel admitted that she was struggling with the waltz but that she hoped her determination and perseverance would carry her through.
"I've put so much effort in over the past few weeks," said Rachel. "I really hope my two left feet don't let me down on the night."