Cara Delevingne and St. Vincent are said to be head over heels in love.

The model was first romantically linked to the singer, real name Anne Clark, in late February and they've since frequently been snapped together.

After Anne uploaded a photo on Instagram of a handwritten note saying "Marry Me Annie Clark", fans were quick to speculate a proposal could be a possibility for the pair.

"Cara and Annie are head over heels, but I don't think marriage is on the cards yet. But Cara has certainly never been this happy with someone," an insider told British magazine Grazia.

Cara, 22, has had her fair share of high-profile romances, having previously been linked to One Direction star Harry Styles and actress Michelle Rodriguez.

But all her attention is now said to be on 32-year-old Anne, and the pair will reportedly finally get to spend some quality time together.

"Annie will be working on another album, so that means she can spend more time with Cara. Cara is about to start promoting Paper Towns, but Annie will be able to travel with her," the source explained.

Cara has recently made the move from catwalk queen to actress, winning praise for her role in The Face of an Angel.

Her time away from the fash pack, as well as her alleged romance, means Cara is now content with leading a quieter life.

"Annie is a little older than Cara and has actually been a really good influence. She's really settled her and made Cara realise she doesn't have to go out every night. She's just as happy staying in with Annie in matching dressing gowns or going out on a date. They really are peas in a pod," the insider smiled.