Clare Balding fears she will be judged on her appearance as she "glams up" to host a new Saturday night BBC One show.
The 41-year-old sports presenter, who won accolades for the way she covered the Olympics and Paralympics, is set to present prime-time entertainment show Britain's Brightest.
She told the Radio Times: "I'm putting myself into a different genre - I'm therefore saying to the public, 'Can you accept me in a completely different format?' and that is risky.
"And obviously because it's Saturday night, I've got to glam up a bit. You know, there will be a few people who go, 'Oh, I don't like what she's wearing'."
Clare was interviewed while filming the series, wearing six-inch heels.
"I'm not running in them, am I? Mainly, I'm just walking three steps and stopping," she said.
When the interviewer said they look a bit "dominatrix", she responded: "Dominatrix! Don't you dare write that!"
Clare will also be hosting Good Morning Sunday on Radio 2, replacing Aled Jones on the weekly faith programme. Asked whether she had a faith, she said it was "not significant" adding: "I'm very interested in other people's faith and I think that's what matters."
Clare said that her new "national treasure" label would not last, and she added: "I think 'ambitious' is one of those adjectives used for women in a derogatory way - and, yet, I think ambition is crucial in life - you have to know what you might be capable of and push yourself slightly beyond it."
Asked whether she would ever consider hosting a chat show, Clare, whose civil partner is Radio 4 newsreader Alice Arnold, said: "I don't know whether a chat show isn't pushing it too far."