She’s only four months old, but Jessica Simpson’s baby has already posed for her first bikini shot, RadarOnline.com is reporting.

Little Maxwell Johnson was pictured in a snap on the premiere of Katie Couric’s daytime talk show in a two-piece crochet swimsuit on Monday. Meanwhile her mother told the former TODAY host that despite losing more than 18 kilos of pregnancy weight, she was still nervous about her appearance.

She said: “I almost peed my pants. I’m very nervous.” Couric also treated her viewers to a sneak peek of the first Weight Watchers commercial featuring Simpson as their new spokesperson – Jessica is shot from the shoulders up, when asked why she didn’t reveal her body the singer said: “I really didn’t want it to be about my weight because I know that everybody has…their own issues and I really wanted it to be about the spirit of Weight Watchers and how I was feeling and I wanted to talk directly to people. I didn’t want the big body reveal moment. It’s not really who I am....”

Simpson refused to reveal exactly how much weight she has lost so far saying it’s “not about the numbers.” But she did say she has 5 kilos left to go.

In addition to following the eating plan Simpson is working out by walking with Maxwell in tow. She says: “I basically take her with me, whether it’s strapping her on me or strolling around the neighbourhood.”