Liam Hemsworth

E! News -- If any celebrity coupling can make us believe in true love, then this might be it.

There was a time when Miley Cyrus and Liam Hemsworth were young Hollywood's poster kids for young love. Three years after meeting on the set of The Last Song (in 2009), they got engaged. But then, just 16 months after Liam got down on one knee, they were over.

To say they took different paths post breakup would be an understatement. At first we blamed Liam. A day after the announcement, he was spotted hanging out with Mexican model Eiza Gonz├ílez. But then the focus changed because Miley, well, she just seemed to go a bit off the rails…exhibiting the type of behavior that had us debating whether she should be placed on the same pile as all those other child stars gone wild. For some, her drastic actions (rubbing her crotch against Robin Thicke at the MTV VMAs, and hanging out with a foam finger) made her seem a little too desperate to shed her Disney past, and her former love.

And then, a year after her split with Liam, she met Patrick Schwarzenegger, and temporarily became part of a political dynasty. We should have seen the signs then. Sure, Miley can be in your face, but the kind of person she likes to date needs to be tame and strong enough to balance her eccentric character. Miley and Patrick looked fabulous together, and she seemed to relish in his company, especially when he was with his parents. But that was before Patrick mucked everything by being snapped doing body-shots off a female friend in Mexico.

When she split from Patrick, in the spring of 2015, we got a whiff that something might be brewing again between Miley and Liam. The first unconfirmed spotting of them together was in April last year, and then rumors starting circulating in the summer, but no one took it seriously. Instead we were more focused on whether Miley was dating model Stella Maxwell, and the idea of her reunion with the quiet Australian seemed far-fetched. Their personalities by now were seemingly diametrically opposite. So, we all ignored the obvious clues: Liam adopting his new dog, Dora, with Miley's help; Miley's social media screen grab of a text message from an unknown sender, which simply said, "I love u." Then there was Liam's November interview in Men's Fitness in which he revealed about his relationship with Miley: "It was real. It wasn't just a fling. You fall in love with who you fall in love with, You can never choose. I mean, look—we were together five years. So, I don't think those feelings will ever change. And that's good because that proves to me that it was real. It wasn't just a fling. It really was an important part of my life and always will be."

The truth is that whole time, Liam wasn't far from Miley's mind either. A source reveals to E! News, "Miley has never gotten over Liam and always hoped they would get back together. She doesn't know where it will go but she definitely still loves him and wants to be with him. Liam has an interest in being back together, too."

So, for the past few months, Miley and Liam have been very secretly spending time together, testing things out to see if they are still compatible. "They always stayed in touch and never got over each other. They would text each other or email from time to time just to check in. Liam has always been Miley's No. 1 and she was hoping for this," a source says. "They needed time apart to realize how much they love each other and want to be together. It happened slowly over time. One conversation led to another. It wasn't something that happened overnight. They are both a little bit older and wiser now. They've lived a lot in the last year few years and think things will be different."

"They've spent a lot of time at each other's homes in the last few months reconnecting," the source adds. "They haven't gone out much. They wanted to work on rebuilding things before they went public. They relax at home and watch movies with their animals and order takeout. She's been at his house and he has been at her house. They are both very happy about where things are and going to see what happens."

The real evidence emerged over the Christmas holidays when this very Hollywood love story moved up a notch as Miley was spotted spending time with Liam's family in his native Australia. And then sources really started to spill...

As one told us last week, "She had the time of her life being with him and his family. She feels like they could pick up right where they left off."

Fast forward a week, and before we have barely managed to get over the shock of a reunion, it seems they might have skipped a few of the conventional dating steps and are actually engaged again. This weekend, Miley caused an Internet storm by wearing the 3.5 carat Neil Lane ring Liam bought her back in 2012 on that finger!

The message to the world seems unmistakable. Especially for Miley, a girl, who unlike the majority of her celebrity peers, doesn't have a publicist who talks to the public for her. Her social media is her way of communicating directly with her fans.

Our sources agree, despite an almost three-year gap, this couple is pretty much made for one another. "They are like yin and yang. Liam is so laid back about everything and he really mellows Miley out," an insider says. "But he gets her wild side too and he admires how fun and exciting she is. There's never a dull moment with Miley and he doesn't try to challenge her."

The insider adds, "She likes the way she feels about herself when she's with him."

"They really get each other," another source says. "They don't have to do much and they are having fun. They make each other laugh and can talk for hours. It's an effortless love and they have an undeniable chemistry."

Miley certainly isn't the same girl she was when they met. But neither is Liam the same man. She just needed some space to find herself. She went from child star, to movie star, to almost married—and she wasn't even 21. No wonder things didn't work out. She needed to discover who she was as a person. And in that time while we witnessed her wild nature, we also saw her mature especially when she started the Happie Hippie Foundation (to help homeless youth, LGBTQ youth and other vulnerable populations).

There's a quote that had stuck with me ever since Miley first met Liam back in 2009. She once told Parade magazine, "[Liam] really respects me for who I am because coming from Australia, he really didn't know me as the celebrity I am here. I got to tell him about myself on my own terms and my own way. He had no preconceived notion of who I was supposed to be."

And now, on her own terms and in her own way, she's been able to show him who she really is.

Liam and Miley's love story proves that no matter how famous you are, you can't buy love. A-listers go through the same romantic ups and downs that all of us experience. It's not easy for them either.

Here at E! we've seen this many times before: A celebrity couple splits, and after some time apart, they get back together and only then are they strong enough to stand the test of time (um, hello, Prince William and Kate Middleton!). As the old saying goes: "If you love something set it free. If it comes back it's yours. If not, it was never meant to be." And that seems to be exactly what Liam did.