The singer and presenter, 34, came runner-up on The X Factor in 2014 and has since launched a career on radio and TV.
She said her upcoming stint on the popular BBC One series, which returns on Friday evening, will be in memory of Malcolm.
Explaining why she wanted to do Strictly, the former I’m A Celebrity star said: “Firstly, it’s the best show ever. Secondly, for me it’s a personal reason, my dad passed away in 2020 and this was his favourite show.
“He even used to get annoyed that he had to miss out on Strictly when I was on The X Factor because they were on at the same time.
“When I was deciding whether or not to do it I spoke to my sister and she reminded me of dad watching it all the time and then that was that the deciding factor straightaway, so that’s my motivation for doing it.”
Asked about who her biggest competition will be, she said: “Having watched the show for years, you can’t predict who’s going to do well, so I just think I’m going to focus on myself.
“I’m so hard on myself anyway, I know that I’ll be watching back everything I’ve done picking it apart and trying to compete with my last performance.
“That may be a cheesy answer, but genuinely I can’t suss anyone, because everyone’s going to be different, everyone’s got their own story, everyone’s got their own reason, and it’s lots of different personalities.”
Hits Radio Breakfast Show host East is among the 15 famous faces taking to the dance floor this year, joined by TV presenter Helen Skelton, EastEnders actor James Bye and former England footballer Tony Adams.
Also in the line-up is Ted Lasso actress Ellie Taylor, Paralympic swimming gold medallist Ellie Simmonds, Two Pints Of Lager And A Packet Of Crisps actor Will Mellor, Loose Women star Kaye Adams and Coronation Street actress Kym Marsh.
They are joined by Bros singer Matt Goss, Kiss radio host Tyler West, Britain’s Got Talent finalist Molly Rainford, comedian and actress Jayde Adams, Wildlife cameraman and presenter Hamza Yassin and BBC Radio 2’s Richie Anderson.
Strictly judges Craig Revel Horwood, Motsi Mabuse, Anton Du Beke and head judge Shirley Ballas all return too, alongside hosts Tess Daly and Claudia Winkleman, for the 20th series of the show.
The professionals line-up this year boasts four new faces, alongside returning favourites like last year’s winner Giovanni Pernice, Gorka Marquez, Dianne Buswell, Katya Jones, Nadiya Bychkova, Johannes Radebe and more.
Following the death of the Queen, the launch date was postponed a week until after the monarch’s state funeral on September 19.
The TV competition was due to return to screens on September 17 but the launch show now airs on September 23 followed by the first live show on September 24.
Strictly Come Dancing launches on Friday, September 23 at 7pm on BBC One and BBC iPlayer.