Meghan Trainor Dishes on Her Slim New Look & How Boyfriend Daryl Sabara Helped Her Get Healthy

Meghan Trainor is looking fit and happy, and she's been putting in the work to get there.

ET's Nischelle Turner recently sat down with the judges of Fox's new reality singing competition The Four: Battle for Stardom, and chatted with the "All About that Bass" singer about getting healthy.

"I work out so hard," Trainor, 23, shared. "I've been working on my health [with] my boyfriend and, yeah, we eat good and we work out, like, every day."

Trainor recently shared a few snapshots of her svelte, stylish physique to Instagram, showing off the progress she's made on her fitness journey.

She also shared a snapshot of herself and her boyfriend, actor Daryl Sabara, sharing a sweet moment together backstage on the studio lot.

"Thank you for supporting me with this crazy new adventure," Trainor captioned the cute photo. "YOU are thuuuh love of my life."

Sabara also joined the songstress during her interview, and Trainor opened up about how her beau helped her and encouraged her to take on the challenge of being a judge on the new series.

"We got emotional," she recalled. "It was, like, a long talk and I was like, 'It's a dream of mine to do this, to be a judge on one of these shows, and to help a new artist.' And he was like, 'I didn't know it was a dream of yours. Let's do it! I'm 100 perfect in,' and that was the talk we had a couple nights ago."

In Fox's new reality series, four finalists are chosen from a nationwide audition for singing hopefuls. Then, those four defend their seats against challengers who try to take their place in a singing battle.

The winners of each battle are determined by the panel of judges -- which include Trainor, Sean "Diddy" Combs, DJ Khaled, and record exec Charlie Walk -- and the singer left standing will be named an iHeartMedia "On the Verge" artist.

For Trainor, getting to coach, guide and mentor emerging hopeful artists seems to be her driving motivation behind joining the series, and she opened up about the artists who gave her some of the best advice.

"[Jennifer Lopez] is so great when she spoke to me," Trainor gushed. "I had moment with her and was like, 'How did this performance happen?' and she was like, 'Get Pinterest and take all your pictures.' She does everything. She taught me a lot."

"Sam Smith helped me with [advice] like, 'If you can't sing that night, you gotta cancel the show,'" she continued. "[He gave me] a lot of advice all around."

"I'm [always] trying to find friends that will help me in this industry who have done it longer than I have," she added.

As for what kind of panelist she's going to be on the actual show -- when she has to judge singers and listen to emotional performances -- Trainor says she's going to be "a crier, for sure."

"I can't tell what I'm gonna be, because I've never really done this," she said. "But I think I'll be very honest, and I think I'll cry every episode."

ET also caught up with Diddy, who dished on getting the show together.

According to the 48-year-old rapper and music mogul, he brought DJ Khaled on by convincing him to not pursue a spot on the panel for the upcoming American Idol reboot.

"Khaled was about to really peruse something with American idol and I said, 'I'm tryin to build a super team,' and he's like, 'But I don't know about this show,'" Diddy recalled. "I said, 'Khaled, you got to rock with me. So it's almost like LeBron and Dwyane Wade, when they got together and put together that super team. I can't do this, I can't return to TV without you, baby.'"

"You know what I love about the lineup… everybody has their thing everybody has real amazing personality," Khaled said of the panel. "All work speaks for itself."

The Four: Battle for Stardom -- hosted by pop diva Fergie -- kicks off Jan. 4 at 8 p.m. ET/PT on Fox.

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