The two were enjoying a brunch date in Studio City, California, over the weekend, and judging from their expressions in the steamy snaps, it appears they have developed a close relationship in the eight months they've been working together.
"Gaga has real chemistry with Dan," a source close to Gaga tells ET. "They have been seeing each other for weeks and have been working with each other for a while. They have been working on new music, have spent hours of work time together and became really close."
"They're working very closely together at a home studio in Hollywood, and sparks just started flying," the source adds. "People noticed the chemistry early on, and now that she has taken some time to herself, she finally feels free to date. They seem like a pretty good match."
This is the first time fans have seen Gaga spark up a potential relationship since calling off her engagement with Christian Carino in February. In the months following their breakup, rumors began swirling that the "Shallow" singer had developed feelings for her A Star Is Born co-star, Bradley Cooper, who split from his longtime girlfriend, Irina Shayk, in June.
"All the talk of Bradley was all in fun; she's ready to dispel those rumors once and for all," the source says, adding that "no one" is surprised by Gaga moving on and dating Horton. "He is handsome and talented and she likes to date men on her team ... she is known as a workaholic, so it fits her lifestyle to meet someone while working."
According to our source, their relationship is "just in the beginning stages" -- Gaga plans to take things slow with Horton, who previously worked with stars like Camila Cabello, Bruno Mars, Justin Timberlake, KISS, Lenny Kravitz and JAY-Z.
"Dan's adorable, southern, artsy and very different from the typical Hollywood guy," the source says. "Right now they are having fun and it's convenient. She can talk music with him and knows all the big-name artists he's worked with. She respects his work and sees him as a breath of fresh air."
Gaga's rep did not reply to ET's request for comment.
ET reported earlier this year that Gaga had no drama with Carino and that their relationship "just came to an end."
The Oscar winner addressed the breakup for the first time publicly last month, while on stage during one of her Las Vegas residency shows at Park MGM's Park Theatre. "So, last time I sang this song, I had a ring on my finger," she said moments before singing "Someone to Watch Over Me" while seated at a piano. "So tonight will be different."
Hear more in the video below.
Reporting by Adriane Schwartz.