Rachel was also seen chuckling at a word found by her real-life boyfriend, Strictly Come Dancing star Pasha Kovalev.The 31-year-old Oxford-educated beauty was left red-faced at the word 'Phallus', a term for a penis, much to the cast's amusement.
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'It's happened to me in the emergency department before, as well,' Dr Phil added, to which host Nick Hewer said: 'I think we better move on! This time she went down the designer route, rocking a dress by Peter Pilotto.
' Forget a brain workout, we're going to start tuning into Countdown just for the style inspiration! Nobody does prints quite like Pilotto, and we love the medallion design of this dress.
Rachel, clad in an A-line, abstract patterned dress, was seen stifling a giggle at the word.
She subsequently took to Twitter to share a screengrab of the moment, joking, 'Nothing to see here! The former Strictly favourite's posts was a hit with fans at home - especially of the male variety.'Such filth', one viewer joked, while another posted, 'my word', and a third shared, 'Rachel yer killing me here'.
Finding two eight letter words from the selection on offer, Dr Phil said to Susie: 'I'll let you choose which one you'd like to say first.'Susie picked the safer option which was 'abortive'.
Dr Phil then went on: 'I spotted a vibrator in there as well.'This sent a ripple of chuckles through the studio, as Rachel Riley arranged the letters on her board to spell out the word.
The presenter, 34, struggled to keep her composure after spelling out the innuendo-laden word on the board.
The embarrassing moment came when the two contestants chose the words, 'squirt' and 'squire', only for lexicon-expert Susie Dent to suggest a saucier alternative.
Another viewer joked: 'You owe me a mouthful of coffee and a new monitor!