I reckon Octopus is Myleene Klass....
She's into fashion, she's done modelling and is quite leggy.
She has her own fitness training program (with a sandbell weight) that she sells - called MyBody by Myleene Klass.
She featured on The Apprentice as one of the weekly winners' rewards (a private piano recital!)
She was on the same "I'm A Celebrity" series as Jason Donovan - with the infamous jungle shower scenes of her in her bikini (like Octopus 'splish splashing' in the bathtub under the shower in last night's performance?)
Signed big money deals after I'm a Celeb.
Had her own make-up range.
We know she can sing well and can sing in an operatic style - Davina said that some contestants were disguising accents and some were holding back - Octopus is defo one of those.
Found pics around the internet of her posing as a mermaid and underwater pics from when she learned underwater swimming/diving techniques.
When Octopus sang "Part of Your World" she mentioned her "collection" which could be referencing her
own clothing collections.
Also during that song the set looked like it had a cosmic/space themed background and she's known for being into astronomy in a big way - studied it and presented astronomy stuff on TV.
Octopus mentioned being a role model to kids, something which Myleene has talked about before. Also been involved in loads of kids charities including Childline & a children's music charity.
And finally, I'm sure the fish & chips was also a clue and she apparently famously had fish and chips at her wedding...(although she's now divorced so maybe it's not so relevant after all!)
Her baby Son would've been only a few weeks old when the show was filmed but looking at her Twitter it looks like she was working around then. I'm not sure about the voice but the rest all fits!