In 2004, Lewis took part in the BBC’s “Strictly Come Dancing”. She was partnered alongside professional dancer, Ian Waite and in the first few weeks scored the highest number of points with the judges. She eventually reached the final and was runner-up to actress Jill Halfpenny. Following this, Denise and the two other partners from the final, danced at the Royal Variety Performance. About 10 days after competing in the final of “Strictly”, Denise and Ian competed again in the “Strictly Come Dancing Champion of Champions Special”, where the finalists from both series of the contest, competed against each other. Denise received the most points from the judges; however she once again became the runner up of the contest, as Jill Halfpenny won overall. She again revisited the role for the BBC's charitable fund-raiser “Let's” Dance for Comic Relief in 2009, reaching the final of the competition.
In 2009, Denise was a pundit for BBC Sport's coverage of the 2009 World Athletics Championships from Berlin alongside Michael Johnson and Colin Jackson. In 2010, Denise was a pundit for BBC Sport's coverage of the 2010 Commonwealth Games from Delhi, again alongside Michael Johnson and Colin Jackson. Denise now hosts Camp Orange with Anna Williamson and Jamie Ricker on Nickelodeon (UK & Ireland). Season 1 premiered on July 22nd, 2011.
A “good sport”, Denise played on "All Star Family Fortunes", broadcast on 29 November 2009, with her husband, mum, step son Joe O'Connor and best friend. She went on to win £10,000 for her chosen charity, The African Caribbean Leukaemia Trust.
In July 2011, Lewis appeared on a celebrity edition of the BBC One game show “Pointless” with her father-in-law Tom O'Connor. They reached the final, eventually winning £500 for charity.