The girls jetted off to Mexico to celebrate Chavez's 40th birthday. "Forty is the new 20!" Simpson said of her friend, adding the hashtag #HotMama. "I love this woman."
No doubt Simpson is looking better than ever, and she recently revealed to InStyle her exercise regimen. "I work out five days a week: three days with a trainer, doing a mix of strength training and cardio, and then I do cardio on my own the other two days," she said. "Somehow I make it work, but I've slowed down since my wedding."
When ET spoke to Simpson, she admitted that she doesn't follow a strict diet. "I think being a mom is enough of a diet," she quipped. "You have to run around chasing your kids, but I do eat a lot of their corn dogs, so I have to get on the treadmill a lot to watch my TV shows."