Running into an old flame.

As we kick off Season 27 of “The Bachelor,” we’re looking back on some of the best moments in Bachelor Nation history.

This week, we’re throwing it back to Season 21 of “The Bachelor” when Nick Viall was our leading man.

Today, we’re looking back on a special one-on-one date from Nick’s season where he took Danielle Lombard on a tour of his hometown of Waukesha, Wisconsin.

The two made cookies, shared romantic kisses, and visited the park where Nick had his very first kiss.

At one point during their date, Nick and Danielle ran into one of Nick’s exes as they walked past a coffee shop.

Nick was shocked and said to Danielle, “I know that girl, that girl right there. She’s an ex of mine. I should go say hi.”

Danielle encouraged him to say hello but added, “Nick and I were strolling through downtown and we happened to run into one of his exes named Amber. That was crazy. It kind of threw me off. I wasn’t quite sure how to react.”

Amber ended up sitting down with Danielle and Nick, and Nick called the moment “trippy,” while Amber shared that she and Nick dated for around four months, adding that it “seems like forever ago.”

Danielle decided to ask Amber why she thinks Nick is still single and Amber got candid, saying, “I think if he’s not in it to the point where he feels it, then he backs out. That’s what he’s been missing. He needs something heart-driven and hopefully you find what you’re looking for here.”

Danielle appreciated Amber’s honesty, and while she was thrown off by running into one of Nick’s exes at first, it turned out to be a positive experience.

She said, “I loved talking to Amber. She was really nice and she had nothing but great things to say about Nick. I liked the fact that Nick is on good terms with this ex. That just shows the kind of person he is and how he’s very caring for people that have been in his life.”

Nick chimed in, saying, “This could’ve gone really well or really badly, but I feel like it went really well.”

Later that night, the two were serenaded by country star Chris Lane (who later married fellow Bachelor Nation star Lauren Bushnell Lane).