The ladies arrived separately at their Studio City, Calif., gym, the Tracy Anderson Method Studio, early in the morning – but they were happily chatting (and sweating) together during their long, strenuous workout.
"Yoga stretches are very important to Gisele," a source tells PEOPLE. "She showed Camila a few stretching and abs exercises that are great for new mothers." Trainer Tracy Anderson, whose workouts include Pilates, wasn't present.
Alves has two kids – Levi, 22 months, and daughter Vida, 4 months – with Matthew McConaughey, while Benjamin, Bündchen's son with husband Tom Brady is 5 months.
According to the source, "Gisele and Camila seemed to enjoy working out together – and had fun chatting during the workout." – Pernilla Cedenheim and Ainka Shackleford