The singer, who had not been seen in public and had not posted on social media since September, goes snow tubing with her friends.
The Back To You singer, 26, was pictured with a large group of friends looking happy and relaxed as they went snow tubing in Big Bear Lake ski resort in Southern California.
Her former Wizards Of Waverley Place co-star Bailee Madison and close friend, model Connar Franklin, shared images on their Instagram accounts.
Some eagle-eyed fans also noticed Gomez was wearing a Taylor Swift stadium tour hoodie.
Gomez has not posted on her own Instagram since the end of September, when she announced she was taking a social media break and reminded followers to not post negative comments.
The appearance is one of the first public outings Gomez has made since she left her treatment programme in New York City after entering in October for anxiety and depression.
She suffers from the autoimmune disease Lupus, of which anxiety and depression are common side effects, and had initially been in hospital for a low white blood count.
In 2017 she had a kidney transplant because of the disease, which she was diagnosed with in 2015.
Gomez's reappearance on social media after two-and-a-half months was welcomed by fans, with the hashtag #SelenaIsBack trending worldwide.
Fans reacted to the photos with excitement, saying they had missed her.
Gomez has previously spoken about the downsides of social media and has taken several breaks from her pages before.