Gaga, 33, sparked speculation of a breakup while attending her longtime makeup artist Sarah Tanno’s bachelorette bash on Friday.
Sharing a selfie of herself and the bride-to-be, the singer — who also shared that she was “in a lot of pain” after suffering a nasty fall the previous day — captioned it, “an about to be married woman and me, a single lady.”
The “Shallow” singer and the audio engineer, 37, were last seen together at a concert for The Cure and the Pixies in September.
A rep for Gaga did not immediately respond to PEOPLE’s request for comment.
Gaga and Horton first sparked romance rumors in July, after they were photographed kissing during a brunch date in Los Angeles.
A source told PEOPLE at the time that the pair dined for about an hour and were deep in conversation. “They were kissing as they spoke really close up,” said the source.
“Ironically, she had a table in the front near the sidewalk, so she was clearly okay with being seen,” the source added. “She seemed very happy when interacting with the guy she was with.”
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According to his LinkedIn page, Horton has worked as a monitor engineer for Gaga since November 2018, before she started her Las Vegas residency. He is also the owner of Audio Engineering Consulting Group, according to the site, and has previously worked with other big-name artists such as Camila Cabello, Bruno Mars and Justin Timberlake.
Horton, who is Nashville based, was previously married to actress Autumn Guzzardi, who is currently a castmember in the off-Broadway musical Rock of Ages. The two tied the knot in 2013, and Guzzardi’s most recent Instagram post of the two is from 2016.