The ‘Wizards of Waverly Place’ star had asked her management to book ‘Union J’ to perform with her at a gig in Portugal, the Daily Star reported.
Gomez, who was earlier dating Justin Bieber, invited all the boys to an after party at her hotel room.
A source has revealed that the 21-year-old singer and Shelley were reportedly “all over each other” and things got “very heated” between them.
The 20-year-old boyband member also missed his flight back to London, as he arrived separately from his bandmates.
Shelley was earlier rumoured to be romantically involved with Little Mix’s Jesy Nelson.