Slack CEO Stewart Butterfield is part of the newest 'it' power couple in Silicon Valley - here's what we know about the newly engaged billionaire's relationship with his fiance, who runs a $1.4 billion company

The millionaire executive turned 30 last year; her net worth is estimated to be $130 million.

They're power players in their own right, both running billion-dollar businesses.

Butterfield, who is 16 years Rubio's senior, continues to make headlines after his company, Slack, went public on June 20. Despite running high-profile companies, much of their relationship has been under the radar.

He holds a bachelors degree from the University of Victoria and masters degree from the University of Cambridge. Both degrees are in philosophy.

Before founding Flickr, Butterfield started an online gaming company with his Flickr cofounder and then-wife, Caterina Fake; they were married from 2001 to 2008. The pair — along with Butterfield's friend Jason Classon — originally started an online multiplayer gaming company called Ludicorp.

After the startup failed to raise the money needed, the couple founded the photosharing platform Flickr. The company later sold to Yahoo for $20 million in 2015. Butterfield and Fake joined Yahoo in the acquisition — Butterfield worked there for three years.

The couple separated in 2008 and has one 12-year-old daughter together.

Business Insider's Julie Bort reported that the pair stands to make millions, if not billions, off their stakes in the company. Butterfield's stake is worth over $1.7 billion, while Henderson's is worth over $672 million.

After working at Johnson & Johnson through Penn State's co-op program, Rubio decided to pursue a full-time job offer before completing her last few credits. The professional experience led to positions at Warby Parker and All Saints in London, where she worked as the head of innovation.

The pair met working at Warby Parker and started Away in 2015 after Rubio was forced to buy a new suitcase in an airport. Today, the brand is worth over $1.4 billion.

Rubio has stated she travels over 200,000 miles a year.

When asked about her morning routine in a March 2019 interview with Marie Claire, Rubio said, "Whatever my first thing of the day is, I make sure to wake up three hours before that to workout, read, meditate, catch up on emails, or chat with my boyfriend, since usually we're not in the same place."

She did not, however, specify that the boyfriend is Butterfield.

In January, Rubio shared a photo of the two of them together, captioning the photo, "more keys to lose."

And on March 21, Rubio wished Butterfield a happy birthday by posting a photo of him smiling happily with two ice cream cones in Rome.

Rubio retweeted a Wall Street Journal article reporting the news of the valuation, along with the question: "Let's make today a double-whammy — Jennifer, will you marry me? Promise I'm not just a golddigger."

The tweet confused employees of both companies, eventually causing Rubio to clarify that Butterfield was joking.

"It was just a joke," Rubio told Forbes about the proposal the next day. "... He's very supportive and has a weird sense of humor."

Let's make today a double-whammy — @jennifer, will you marry me? Promise I'm not just a golddigger: https://t.co/CaF9OKkpK1

The slideshow he posted included ten photos of the couple and ended "with one taken just a few minutes" after Butterfield proposed.

The photos, posted three weeks ago, showed Rubio wearing an engagement ring.

"Ms. Rubio said she momentarily wondered if he was only proposing because of Twitter, asking, 'Are you serious?'" reported The Times.

No immediate wedding plans have been announced.