It was recently announced that the interior designer will join Ty Pennington and his team for the upcoming season of the ABC show.
Speaking to People, she said: "Bachelor was just something that happened to me. It wasn't anything I was looking for or wanting. It was a fluke, a lark. It was fun to do.
"I got to travel around the world, work with great people who are still friends, and kiss five guys in one day! But it's not really who I am... Extreme Makeover is much more who I am."
The reality star - who made a guest appearance on the show earlier this year - previously said that she "can't wait" to begin filming and "make difference", revealing that she has been a fan of the series for years.
Harris appeared on the 13th season of The Bachelor, and later fronted the fifth season of The Bachelorette, where she met fiance Ed Swiderski.