Nadine Coyle begged Sarah Harding not to do 'Celebrity Big Brother'.

The former Girls Aloud singer tuned in every night last month to watch her former band mate compete on the reality TV show and, although the blonde beauty went on to win the series, Nadine has admitted she was completely against her entering the house.

Speaking to The Sun newspaper, she said: "I was petrified. She called to tell me she was doing it and my immediate thing was, 'Don't. Absolutely not. Why? Stop this immediately. Retract, retract. Don't do it. Just don't do it. We'll go on a holiday. I'm going to Spain, come.' But she wanted to do it. And Sarah's you know, if she's got it in her mind she's going to do something, she's going to go and do it."

Before she went into the famous abode, Nadine was the only member of the girl group to wish her luck and Cheryl Tweedy even unfollowed Sarah on social media.

Nadine, 32, said: "I'm not surprised, no.

"If you don't like someone, just be genuine abut it. You don't have to be anything else. I don't think Sarah's surprised either, it's to be expected."

Sarah's erratic behaviour on the show became the hot topic of conversation but Nadine regularly jumped to her defence to confirm she was being 100 per cent "natural."

She said at the time: "Inside info on Sarah, she is a very natural being. She dwells on of her feelings & acts on them. It is what makes her so unique."

"#nofiler was made for Sarah!!!

"Those of us who know & love her know that. The support from you guys will mean the world to her!! Xx" followed by three heart emojis.

And she concluded by saying: "If I was there, no one would DARE utter a bad word to her!!!!! Xx (sic)" followed by three angel and kiss emojis.