Photo: All rights reserved.

Robin Thicke and April Love Geary

Robin Thicke's fiancee has brushed off rumours suggesting the singer got a little too close to Khloe Kardashian at her sister Kourtney's 40th birthday party.

The Blurred Lines hitmaker and model April Love Geary were among the celebrity guests at Thursday's private bash, held at the Los Angeles home of family matriarch Kris Jenner, where Robin teamed up with fellow singer Sia to sing Happy Birthday to Kourtney Kardashian.

In various social media posts from the event, Robin was caught on camera with one arm wrapped around Khloe's waist, while the reality TV star leaned in closely for a tight hug as the musician appeared to be saying something in her ear.

The image prompted some gossips to speculate about the nature of their relationship, even though Kardashian fans were less than convinced.

One devotee behind the khloekvideo fan account wrote, "Watch there be rumours of Khloe and @robinthicke dating all because of this snapchat of them hugging and talking."

The post caught April's eye and she decided to share her feelings about the unfounded claims in the comments section, jokingly making it clear she approved of the pairing.

"I STAN!!!!" she enthusiastically replied, using the slang term for an obsessed fan.

She and Robin have been dating since 2015, following the 42 year old's split from his ex-wife, actress Paula Patton, the mother of his nine-year-old son Julian.

April and Robin have since become parents to one-year-old daughter Mia, and her baby sister Lola, who was born in February. They became engaged over Christmas.

Meanwhile, Khloe has been single since calling it quits with her baby daddy, basketball player Tristan Thompson, for a second time earlier this year amid allegations of his infidelity.