Becca reportedly reposted Thomas' heartfelt message and wrote, "What a difference half a year makes."
Becca captioned a photo of the couple kissing and added, "These have been the best 6 months of my life, and that's thanks to you, @thomasjacobs (and Leo & Sofia of course). 2021 rocks."
Becca also gushed about Thomas late last week on Instagram when she uploaded an image of him sipping on a flight of different wines.
"Getting hints of tall, dark and handsome with a bold taste of my future," Becca wrote alongside the picture.
Thomas commented in reply, "Nothing in this world I wouldn't do for you."
Becca and Thomas' relationship appeared to become quite serious when the Season 14 The Bachelorette star brought the bachelor home to Minnesota to meet her family for Thanksgiving.
"This past week was one of the best yet and my heart is so full -- not only was I able to spend Thanksgiving with my family (last year was a bust, thanks Covid) but I was able to bring @thomasajacobs home to meet the most important people in my life," Becca wrote on Instagram in late November.
"And show him all of the special Minnesotan places that made me who I am today. Thank you Tommy, for soaking it all in and appreciating the little things. Next time we will get you some snow."
On Bachelor in Paradise's Season 7 finale, Becca was shown breaking up with Thomas and crushing his heart before overnight Fantasy Suite dates because, despite having "an incredible start" to a relationship, Becca worried their romance was "too good to be true."
Becca, coming off two broken engagements, didn't want to leave The Bachelor franchise for the third time with a man unless she knew everything about him, including how he'd face adversity.
Bachelor in Paradise's finale concluded, however, with an update on Becca and Thomas' relationship that revealed the pair had reunited after filming ended and are now dating, "happy and in love."
On Becca's way out of Paradise, a teary-eyed Thomas admitted he was "falling in love" with her and had so much faith in what they had and what their future could be like together, which made Becca question her decision and feel regretful.
Thomas confirmed that he had no hesitation or reservations about giving Becca another chance.
"I had zero fear in my body," Thomas admitted to Hollywood Life. "I was just 100 percent focused on the relationship I wanted and the person who I wanted to be with."
Thomas said, in fact, that he and Becca got back together "immediately" upon seeing each other again.
"It was right where we left off and it's growing every day since then," Thomas shared. "Since then, we've probably spent no more than five days apart and it's been awesome."
Thomas concluded that "life's amazing" now with Becca by his side.
Before appearing on Paradise, Thomas competed for Katie Thurston's heart on The Bachelorette's seventeenth season earlier this year and was portrayed as a villain.
Becca had two failed public relationships before meeting Thomas with Season 22 The Bachelor star Arie Luyendyk Jr. and Becca's The Bachelorette 14 winner Garrett Yrigoyen.
On The Bachelor's 22nd season in 2018, Arie broke up with Becca and ended their engagement because he decided he was still in love with his runner-up, Lauren Burnham, who is now his wife and the mother of his three children.
Becca later thought she had found The One in Garrett, but she announced their split in September 2020.
"I never felt like those two men, you know, we had promised our lives to each other at one point and I had the ring. We were committed for a short amount of time, but I never felt like they were all in, like, ready to fight," Becca said on an October episode of the "Talking It Out with Bachelor Nation" podcast hosted by The Bachelorette alums Mike Johnson and Bryan Abasolo.
"And for both of those breakups, there wasn't much dialogue or passion, it... more so just ended in the way that it did," she elaborated.
It apparently took no time at all for Becca to reach the conclusion she and Thomas are meant to be.
"I'm gonna probably hate myself for actually admitting this to anyone, but I called my mom -- and even though I was engaged twice in the past -- I was like, 'Mom, I think I want to marry this guy,'" Becca shared with Mike and Bryan.
"It's the first time I've ever actually said that out loud."
Becca also revealed Thomas has sent her "multiple text messages" asking about engagement rings, even though he playfully requested that she be the one to propose marriage to him this time.
"It's something we've talked about," Thomas disclosed on the "Talking It Out" episode. "I mean, I don't want to spend my life with anybody else... I wouldn't want to wake up next to anybody else."