Taylor Swift

E! News Melanie Bromley -- A few weeks ago, Taylor Swift and her new boyfriend Calvin Harris held a very special dinner party at his $15 million Hollywood Hills estate. The invite list was tiny. Handpicked, with only trusted friends at the table. It was a sign of intimacy, and proof that Taylor's new romance is getting serious. "They were really happy together, " says a source. "They were sharing hosting responsibilities, it's cute!"

It's a far cry from the Taylor we've all come to grow and love over the past few years. After a string of failed relationships with Harry Styles, John Mayer, Joe Jonas, Taylor Lautner and Jake Gyllenhaal, she's become the poster child for heartache. The reformed serial dater hasn't been shy about it, using every snippet of experience to share details, through her music, about her famous mistakes. And from her lyrics, it didn't seem like Taylor was looking to settle down anytime soon.

But then she met Calvin Harris and somehow he was able to change the unlucky in love soundtrack she had on repeat. According to a source, when they bumped into each other at the Brit Awards in London in February, "He was immediately smitten."

Clandestine meetups at his super-private house in Beverly Hills followed. Giving them a safe place to get to know one another away from the prying eyes of the paparazzi. And then, just weeks later, pictures of them emerged. They were shopping for groceries while wearing matching outfits, and holding hands at a concert. A new celebrity power couple was born.

Here are five reasons why Taylor may have finally found her Mr. Right.

1. They Have Crazy Chemistry: Let's try to forget for a moment that these two actually look like they could be twins. Both fair-haired, tall, same bone structure...picking a partner who is similar in looks is not unusual; it's a phenomenon psychologists obsess over.

And according to our well-placed insider, Taylor and Calvin just clicked. "When they bumped into each other at the Brit Awards, it was instant. They just seemed to get one another. Aside from the incredible chemistry, here was a woman that really understood Calvin's world and vice versa. She's funny and a good person and Calvin's very charismatic, it was like 'bam.'"

2. They Are in the Same Place, Career-Wise: Taylor and Calvin are industry powerhouses. In other words, they have more money than you or I can ever dream of.

She's mega-talented and has seven Grammy awards to polish. Calvin was just named the richest DJ in the world earning $66 million in 2014, according to Forbes (2 million more than Taylor. She made a paltry $64 million).

And they both have longevity in their careers. With Taylor writing her own music, and Calvin deejaying and producing, not just for himself but other artists too (such as Rihanna), neither looks to be stopping anytime soon. The fact they are talented and have chosen the same career path is a big appeal to both of them.

It solves a problem, which Taylor lamented about just a few months ago when she spoke to Britain's Telegraph newspaper; "No one is going to sign up for [being in a relationship with her] and everything that goes with it. Like, 'Hi, nice to meet you, want a date? Do you love camera flashes? I hope you do!' I don't know what's going to happen if I'm ever content in a relationship – no idea how that's going to work. I don't even know if that's possible with the life I have."

But if anyone can relate, it's Calvin.

"Women throw themselves at him," says one friend. "He can never tell if they are really interested in him as a person or if the attention is just because of his fame and fortune.

"But when he met Taylor, it was different. For the first time in a long time here was someone who was his equal. They have a mutual respect for one another. They understand one another. They are on the same level and that's been a good starting point for both of them."

3. They Have Mutual Friends: Hollywood's newest power couple share a lot of mutual friends, and those in their circle can't believe it took them this long to get together. "They are kind of made for one another, " says one. "It's so obvious now when you see them together. This should have happened a while ago."

Having shared friends has created an immediate familiarity and bonded them even further, "They knew from the get go that they could trust one another, which is unusual in their world."

Their interests are similar too (aside from music). Calvin might be a heartthrob, but underneath that DJ fa├žade, he's a bit of a lovable geek who likes to be low-key when he is not on the stage. "He's always been a bit of a nerd, in that cool way, " says our source. "He's a sweetheart, he's funny, but he's never going to be the asshole, it's just not in his nature." And as Taylor's 30 million Instagram followers will testify, she has homebody traits too. Especially if it means she can curl up on the couch with Meredith Grey and Olivia Benson.

"They are surprisingly similar, " says a source. "They have the same interests. They like to hang out together in small groups with close friends. They have dinner parties; they act like a regular couple. It's a very mature relationship."

4. They Both Know What Heartbreak Feels Like: Taylor and Calvin have not had it easy when it comes to love. Both have had their hearts broken. Taylor's turmoils have been well-documented in the songs she writes, but Calvin… "Rita Ora totally broke his heart," says someone who spent time with Calvin at the time of the breakup. "She completely took him by surprise and he wasn't expecting it. It hurt him. He trusted Rita. He thought she was different. He never expected to feel betrayed."

But the nights of crying into their pillows are long gone for both Taylor and Calvin. "They both know the danger of having a relationship in the public eye. And also, what it feels like to be hurt publicly. They want to move carefully because of that."

5. They Both Believe in Happy Ever After: Sources agree, both Calvin and Taylor are happiest when they are in love. The fact these two tick all the boxes with their mutual interests, shared goals and similar cheekbones, means that Calvin and Taylor really could go the distance.

"Calvin is a family guy. He's a regular guy that just so happened to become super-famous," says a friend. "Taylor is very special. Calvin has become very protective of her. He wants it to work. He respects her. They are determined to protect what they have."

But the year ahead may be hard for them. Conflicting schedules are a never-ending problem for even the strongest celebrity couples. Taylor is about to begin her 1989 world tour, and Calvin's gigs take him all over the world. But if they can make it work, as their friends hope and think they can, then Taylor will soon have to look elsewhere for inspiration for her hit songs.

For more Taylor and Calvin scoop, watch E! News.