Billie Eilish’s Boyfriend Nat Wolff Hopes Their Romance ‘Leads to Marriage’: ‘He’s Head Over Heels’

Love is definitely in the air for Billie Eilish and Nat Wolff!

The Grammy-winning superstar, 23, and the Fault in Our Stars actor, 30, are getting more serious by the day — and, according to a source, marriage might be on the horizon if Wolff has any say in the matter.

“Nat is head over heels for Billie and quietly hoping it leads to marriage,” the source tells Star. “The romance is progressing beautifully, but both sides are wary about rushing into anything too fast.”

What started as a friendship between the musical collaborators has blossomed into something much deeper. “The first thing you have to know about the Billie and Nat relationship is that it began very organically,” explains the source. “They were friends, then they did some collaborating and it grew into something else.”

The couple first confirmed their romance with steamy balcony kisses during a passionate Italian getaway in Venice this past June, but their connection runs much deeper than physical attraction.

“Billie has every reason to believe he’s coming from a good, honorable place,” says the source, noting that Nat’s reputation as a “smart, responsible guy” has won over the notoriously private singer.

Despite their seven-year age gap, the pair have found a perfect balance. “She’s in awe of Nat and really is his biggest fan,” adds the source. “They’re not worried about what their fans think because they are too into one another.”

Nat and his brother Alex joined Billie on her Hit Me Hard and Soft tour last year, where their professional collaboration turned personal.

“This is becoming much more than a simple summer fling!” adds the source.