The 24-year-old admitted that the revealing costumes she wears on set are not her style.
"It is embarrassing," she explained. "I've been on set the past couple of days where I've had to a red dress that was up my bum and my boobs were out, and I just think 'This is not me, I would never wear this, I don't have the confidence to wear this', but it's fine, because it's Theresa, I'm in character.
"And it helps to bring the character out when I'm in skimpy outfits because it's totally not me."
The soapstar also said that despite having worn form-fitting costumes during her appearance on Dancing on Ice earlier this year, she does not feel under pressure to stay particularly toned.
"As a kid I used to be really paranoid about it but I don't think about it anymore," she said.
"If I'm full up with food, I just won't stuff myself anymore. I think that's the last thing in the world you should worry about, your weight.
"You should just worry about how your family are stuff, and meeting up with your friends."
Porter was recently photographed topless in Cosmopolitan magazine as part of a campaign to raise awareness of breast cancer.
She recreated Janet Jackson's famous pose that appeared on the cover of Rolling Stone alongside her on-screen boyfriend James Atherton.
Hollyoaks Later returns to E4 on Monday, September 17 at 10pm.