They’re one of the showbiz world’s most enduring couples.

And Rosie Huntington-Whiteley made sure everyone knew her feelings about long-term boyfriend Jason Statham on Sunday, as she marked his 48th birthday with a loving photo.

The leggy beauty, 28, was sat on her handsome man’s knee while the pair were on what appeared to be a night-time date.

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So sweet: Rosie Huntington-Whiteley shared an adorable snap of herself sat on boyfriend Jason Statham’s knee to mark his 48th birthday on Sunday

The hunky actor happily grabbed onto his lovely lady as he smiled up at her, while she flashed a rather sizeable amount of her enviable leg thanks to her tiny dress riding up.

But she didn’t seem to care as she placed her arm aro

It appeared to be quite the intimate birthday celebration for the Fast & Furious 7 actor and his girlfriend, as they were in an upscale-looking bar, with Rosie clutching a drink in her hand during the sweet embrace.

Along with the photo, shared with the model’s 3.6m Instagram followers, she simply added: ‘HBD my love.’

Casual couple: Rosie and Jason – who have been in a relationship for over five years – were spotted heading to New York from Los Angeles together on Thursday

Don’t let go: The stylish 28-year-model made sure to hold on tightly to her handsome man’s arm as they walked through the terminal at LAX

However, clearly feeling besotted with her beau, she substituted the ‘love’ for a little heart symbol on the social networking site.

The passion between the pair was clearly mutual, with Jason looking just as head-over-heels as his ex-Victoria’s Secret beauty as he did when they first got together.

They were last seen together on Thursday, leaving Los Angeles via LAX and heading to New York, presumably the location of their late-night and super-romantic date on Jason’s 48th birthday.

Rosie and Jason have, despite their increasingly busy schedules and the 20-year age gap between them, stood the test of time, having been a close-knit item for over five years.

And, although they appear sporadically at high-profile events together – such as they did at the BRITs afterparty this year – the couple are mostly quite low-key, something that has no doubt helped keep them going all this time.

PDA: Earlier this year, Jason and Rosie put on a loving display as they attended the Universal Music BRIT Awards afterparty

The British twosome mostly spend their time together in Los Angeles, where they share a home with their two dachsund dogs.

Earlier this year, smitten Rosie opened up in a rare chat about her boyfriend, admitting that their romance is different from her previous relationships.

Speaking to SELF magazine, she said: ‘We’re best mates. He makes me laugh every day. I almost feel like I never had a proper boyfriend before!’

She also revealed that their knack for staying out of the public eye isn’t something they do on purpose.

‘Kids are in our future’: In a previous interview, former Victoria’s Secret model Rosie admitted she and Jason are thinking about starting a family

‘It’s more work to put your relationship out there than it is to keep it behind closed doors. But my relationship is not a branch of my brand.

‘It’s my private life. Certainly, that’s how he feels, too’, she explained, before adding further details about their hopes for the future.

‘For any couple that’s been together for a certain amount of time, there’s a massive amount of pressure to get married.’

‘I totally believe in marriage, but being in a happy relationship is much more important to me… [Kids are] something that’s more realistic in the near future.’

Still going strong: The British couple, who live together in Los Angeles, have been together for over five years, after getting together in April 2010