Greg, 27, presented himself to ABC as a marketing sales representative from Edison, NJ, but an insider told The Sun in June that Greg was "lying" about his career and is actually a trained actor with "a big ego."
"So many of us that know Greg are equally shocked and appalled at how different he's coming off on the show. Beyond phony," the source said on Monday.
When Greg met Katie on Night 1 of The Bachelorette's seventeenth season, he came across very nervous, sweet and reserved. In fact, Katie felt inspired to give Greg the First Impression Rose because she thought his lack of confidence was endearing and the suitor needed some validation.
"First of all, he's not shy or awkward like he's trying to come off as on TV," the source continued. "Quite the opposite."
The source went on to paint Greg in a very unflattering light, suggesting the bachelor has a history of manipulating women and breaking their hearts.
"Greg gets everything handed to him, gets away with bad behavior, and leaves girls either heartbroken and questioning themselves, or both," the source claimed.
"Then he discards them and starts fresh with a new girl with the same exact innocent boy act. He has zero sense of accountability."
Greg discussed having many insecurities with Katie on Monday night's episode of The Bachelorette, saying he's often teased by his sister and had been bullied in middle school, but the source claimed Greg is actually full of himself.
"He grew up with people telling him how 'hot and great' he was. He knows it and he uses it," the source alleged.
Last month, The Sun reported Greg's "passion" is acting and he had attended the prestigious New York City acting school, William Esper Studio, from 2017-2019.
Not only has Greg's acting ambition gone unmentioned on The Bachelorette, but there is also no acknowledgement of the bachelor having attended this school on his public accounts.
"He's always wanted to pursue an on-camera career," the insider said at the time, adding that Greg allegedly scrubbed previous on-camera work he's done from his social media and LinkedIn profile to give the impression he's not trying to boost his acting career.
Greg's LinkedIn page says Greg only began working for a New York-based marketing company called Mondo in November 2020, meaning he became an employee at the company only a few months before leaving to film for The Bachelorette this year.
However, The Sun reached out to Mondo and the company was unable to verify if Greg is an employee.
It appears Katie eventually caught on to Greg's alleged act because she was caught "liking" and later "unliking" a meme that read, "When the guy next to you, [Thomas Jacobs], is getting interrogated about wanting to be [The Bachelor star] and you've gotta pretend to be disgusted while hiding your acting career aspirations," according to Us Weekly.
The meme featured Greg putting his hand over his face in distress and was posted by The Bachelor Season 22 alum Bekah Martinez's podcast "Chatty Broads" on June 22.
Katie also subsequently took to her Instagram Stories and posted a video of herself listening to Olivia Rodrigo's breakup anthem "Traitor," which many fans believed was The Bachelorette star slamming Greg once again.
After Katie reportedly "liked" and "unliked" the meme about Greg's alleged shady aspirations to become an actor, Greg's sister Samantha Collova dished it right back to Katie.
The Bachelor fan Instagram account @Bachelorteaspill posted a screenshot of Samantha's since-deleted comment that, according to Us, read, "[Katie] likes this post but was such a supporter of removing the toxicity and mean girls when she was on [Matt James' The Bachelor] season, you'd think if those intentions [were] genuine she'd had just as much of an issue with this post as well."
Samantha allegedly added in the comment, "Really disappointed in this."
Bekah -- who competed for Arie Luyendyk Jr.'s heart on The Bachelor's 22nd season -- made it known, however, her meme about Greg was intended to be light-hearted and funny.
In the face of backlash, Bekah wrote in the comments section of her meme post, "IT'S A JOKE PEOPLE, I WENT ON THE SHOW 4 CLOUT TOO OKAY. I JUST HATE GREG."
And as shown in the latest The Bachelorette episode, Greg secured a second one-on-one date with Katie when a couple of bachelors were still waiting for their first chance to have a solo date with the Season 17 star.
Katie has admitted she's "falling in love" with Greg on the show, and Greg in turn has insisted he adores Katie and feels they're meant to be together.
"I'm falling so in love with her. I think I've found the love of my life. She's made me love more than I ever thought I could," Greg gushed in a confessional.