Britney Spears' new fianc Jason Trawick pulled out all the stops when choosing an engagement ring.

The 40-year-old Hollywood agent reportedly spent $92,000 on the sparkler and made sure it was perfect for the pop star.

An insider told Life & Style that Jason went down on one knee during a romantic dinner at the couple's Los Angeles home last week and popped the question with a Neil Lane engagement ring.

"Jason helped design a four-carat round cut diamond and platinum ring that has diamonds all around the band," the source said. "It's gorgeous."

Jason had apparently shopped at several exclusive jewellery stores in LA including Harry Winston and Tiffany, but settled on a band by celebrity favourite Neil Lane.

"He looked for a while for the perfect ring and chose it all by himself," the friend said.

"By now he knows what Britney likes. Jason's never been engaged before, so he's really, really excited. He's thrilled that Britney will be his wife. They're both happy. They've come a long way."