Is love at first sight real? Meghan Trainor thinks so — but what about relationship experts?

Meghan Trainor is opening up about her engagement to actor Daryl Sabara, revealing that she knew he was “the One” on their first date.

On Wednesday, the 24-year-old singer told “Today” co-host Hoda Kobt that actress Chloë Grace Moretz introduced the pair after Trainor said, “I need you to find me a nice guy.” On their double date at a bowling alley — which she marks as the date of their “anniversary” — Sabara laid on the charm.

“I think that’s when I knew,” said Trainor. “He came up to me during bowling and said, ‘I just want to know about you. Just tell me more about you.’ And I was like, ‘what does that mean?’

“We talked about getting married [by] month one,” Trainor said. “I was aggressive. I wrote a song called ‘Marry Me.’” The singer added: “He’s such a gentleman, and every door, to this day, that I go through, he opens it.”

But is it possible to know whether someone is the One so quickly after meeting? Many would say yes — Nicole Kidman and Keith Urban got engaged after one month of dating, Cameron Diaz and Benji Maddon tied the knot after a seven-month courtship, and George and Amal Clooney dated for six months before he popped the question.

Biology can explain why some feel the rush of love almost instantly, and it involves two different brain systems. The first is romantic love. “When you first fall in love, the brain is flooded with dopamine, a stimulating chemical that suppresses the appetite,” Helen Fisher, a biological anthropologist at Rutgers University, told Yahoo Lifestyle back in July. “When people experience a rush of dopamine, they can’t sleep at night because they’re thinking about the other person, they fixate over whether that person will text them back, and they feel optimistic and sexually possessive.”

The second, attachment, is when people start to feel comfortable revealing their flaws to each other. “There’s a sense of calm and comfort, and it’s common to feel at times as though you both love and hate that person,” explained Fisher. From an evolutionary perspective, attachment is necessary for couples to stick together long enough to raise children after those lustful feelings have dialed down a bit.

However, there are risks to acting on your feelings during the first few months of courtship, says Bethany Marshall, a Beverly Hills, Calif., psychoanalyst. “When couples first meet, the chemical rush of emotion causes them to idolize each other — almost like their brains are on cocaine — and ignore red flags or negative traits,” she tells Yahoo Lifestyle.

And when couples make big decisions (like marriage) while experiencing romantic love, it’s easy to confuse excitement or gratitude for small gestures (opening doors, texting 24/7) with long-lasting love.

Mature relationships, no matter their length, thrive in a gray area and with the ability to see a partner in their entirety, notes Marshall. “If you can only see a person’s positive qualities, you have a partial idea of who they are and as a result, even the smallest offense can seem catastrophic.”

Couples should also be mutually invested in each other and on equal footing when it comes to the intensity of their feelings. If one person is smitten and the other lukewarm, says Marshall, “the relationship will be fragile.”

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