Kevin Jonas' marriage has got "better and better" every year

Alongside a series of throwback photographs, Kevin wrote on Instagram: "15 years later... feels like this was just yesterday. Every year with you gets better and better!! I love you, @daniellejonas. (sic)"

The Jonas Brothers star - who has daughters Alena, ten, and Valentina, eight, with Danielle - previously revealed that good communication has been the key to his marriage over the years.

Kevin noted that married life is "not that hard when you're with your best friend".

The pop singer - who stars alongside his siblings, Joe Jonas and Nick Jonas, in the The Jonas Brothers - told E! News: "Just being present when we're together [is key].

"We communicate a lot. We talk a lot on the phone. Honestly, I know it sounds weird, but it's not that hard when you're with your best friend."

Despite this, Kevin acknowledged that married life isn't always easy.

The 'Sucker' hitmaker observed that hard work and commitment is needed in order to forge a happy, sustainable romance.

He explained: "Yes, marriage is difficult. There are times where it's hard, and you gotta work through that. But like, it's also, like, not that tough."

The loved-up duo met each back in 2007, and Danielle feels that they've grown together over the years.

The 38-year-old TV personality said: "We really grew together. We got married really young, but we didn't grow separately. We grew together."