The singer's ex-boyfriend Justin Bieber, 23, was spotted arriving at her home in the Studio City neighborhood of Los Angeles on Sunday, according to TMZ.
The website reported that first Justin rolled up in his Mercedes G-Wagon with Selena, 25, arriving just a few minutes later
Sources told TMZ that the former couple hung out until about midnight with mutual friends also joining them.
The pair reconnected after Selena went public last month with the news that she had undergone a kidney transplant due to complications of lupus.
TMZ also claimed Selena and Justin spent time together too last week.
It comes as the Biebs has moved into a luxury $55,000-a-month rental in an exclusive neighborhood in Beverly Hills.
However, the former Disney starlet's romance with rapper The Weeknd is still going strong and he was 'fully aware' that his fellow Canadian was seeing his girlfriend.
The hitmaker - real name Abel Tesfaye - is currently on tour.
Selena and The Weeknd made their public debut as a couple at the Met Gala in May. He has been supportive of her during her kidney transplant and recovery.
Justin and Selena confirmed their rumored romance in early 2011 and dated on and off until breaking up for good in late 2014.
Meanwhile, Gomez had another reunion when she met up with her former Barney & Friends co-star Demi Lovato at the InStyle awards in LA.
The two posed for photos in their glamorous gowns at the star-studded gala.
The one-time child stars showed off their mature styles with Lovato looking lovely in lilac while Gomez opted for classic black.