The Destiny's Child popstar has failed to meet the judges' expectations so far during the series and ended up in the bottom two last weekend. She will also be without her regular professional dance partner Brendan Cole, who has flown to New Zealand following the death of his father.
Paddy Power currently ranks Williams as the 9/4 joint favourite to exit this weekend alongside ex-England goalkeeper Peter Shilton.
Patsy Kensit (7/2), Felicity Kendall (8/1), Ann Widdecombe (10/1), Tina O'Brien (16/1) and Gavin Henson (10/1) are also thought to potentially be in danger of elimination.
Meanwhile, Matt Baker (9/4) remains the bookies' favourite to triumph in the series, but EastEnders actor Scott Maslen and Pamela Stephenson are thought to be hot on his heels with odds of 3/1 and 4/1 respectively.