The British star dazzled in a sparkly pink gown as she strutted onto the dance floor for a special appearance to mark the hit TV show's 2000th episode.
Leeds-born Mel - a 35-year-old mum of two now married to American movie producer Stephen Belafonte - had been asked to help judge a sexy paso doble performed by TV star Kyle Massey and his pro-dance partner Lacey Schwimmer.
Mel's own steamy version of the dance, with her season five partner Maksim Chmerkovskiy, had been voted one of the nation's top 10 all-time favourite dances.
The red-hot duet was the highest scoring couple during the season, in September 2007, and made it to the finals before losing the top spot.
Mel, who now lives in Los Angeles, told host Tom Bergeron, 'For me the most difficult part was getting the technique down.
'Because I already had the anger, I was kind of a bit angry back then, but it was the technique.'
At the time, Mel had recently married Belafonte but was still dealing with stress from her previous relationship with funnyman Eddie Murphy, who had refused to accept he was the father of her daughter Angel Iris.