Rob Kardashian and Cheryl Burke
Jason LaVeris/FilmMagic; Frazer Harrison/WWE 2011/Getty
10/02/2011 at 04:00 PM EDT
Rob did a great job last week
on Dancing with the Stars
. He was really feeling the dance. I think it gave him some confidence with the judges. And he was really happy, especially when Carrie Ann told him he was better than his sister
It's just nice to hear positive feedback, especially for Rob. He does have his insecurities and he does have low self-confidence. I think it really pushed him to do even better this week.
Rob's also become more and more competitive. No one wants to get a bad score on Monday night, and the only way to avoid that is to really work hard. He's taken it seriously from the beginning, but I think now he wants to make sure he improves every week.
He's lost a lot of weight. His whole physical appearance has changed. He's using different muscles. He's super sore all the time. I'm not sure if he's changing his diet, but the cardio is really good. I think he lost most of the weight just rehearsing from the jive because it's so fast-paced.
I can tell Rob is getting more comfortable with his body because he's starting to wear tank tops to rehearsals. And you'll see his arms out. In the beginning, you'd never see that. He looks at himself in the mirror. It's really cute.
This week we're doing the foxtrot, and the theme for the couples is "most memorable year of your life." It's a very touching and really sweet story that Rob is telling. People will see more of the sensitive side, and how family-oriented Rob is.
He's a quick learner. He picked up the foxtrot in one day. Now it's a matter of making the quality of the dance good.
Cheryl Burke and Rob Kardashian will perform on Monday's Dancing with the Stars (8 p.m. ET) on ABC.