The on-again couple was spotted leaving hot yoga studio Hot Pilates together in West Hollywood, California, on Wednesday.
Gomez wore royal blue Puma leggings with a white sweatshirt and tennis shoes for the workout. She carried a black purse and her phone in her hand. Meanwhile, Bieber, 23, had on a white tank top, sneakers and white gym shorts with yellow-and-orange strips on the side.
The pair reportedly spent New Year's Eve together in Cabo San Lucas, Mexico. While they weren't photographed together, Selena, 25, appeared on one of her friend's Instagram pics wearing a black one-piece and splashing in the waves.
A source recently told ET that the lovebirds are stronger than ever and are taking their relationship very seriously. "Emotions were high after [her kidney] surgery, so it was the perfect opportunity for them to reunite,” the source explained. "Justin and Selena really bonded over their faith and feel like this is a brand new relationship -- even if other people don’t see it that way.”