At last it seems everyone's favourite friend has something to smile about.

Jennifer Aniston, who turned 39 last week, has apparently been enjoying a romance with her dashing leading man, Aaron Eckhart.

Insiders say the popular actress and Eckhart, who is also the same age, have become inseparable on the set of 'Travelling' in Vancouver, Canada.

And The Daily Mail has learned that shortly before beginning the project, Eckhart, who personally requested Aniston for the part, ended his relationship with his longtime girlfriend Ashley Wicks.

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Unlucky-in-love no more? Jennifer Aniston is apparently enjoying a romance with her latest leading man, the handsome Aaron Eckhart

"They're getting along so great that everyone on the set is gossiping about something more going on between them," said an on-set source.

"They're just so in sync all the time.

"And Jen's entire reason for doing this movie was Aaron.

"She's wanted to work with him for years and was completely flattered that she was his first choice to be the leading lady in this movie.

"It's going to be a real change of pace for Jen, who has focused exclusively on making romantic comedies.

"This is more of a quirky romantic drama with lots of intense scenes opposite Aaron. They're in almost every scene together."

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The couple have become inseparable on the set of drama 'Travelling' in Vancouver, Canada

Aniston, who was left heartbroken when her marriage to Brad Pitt ended in 2005 and his subsequent romance with Angelina Jolie, has been involved in a series of short-lived romances since.

Following an on-off relationship with Vince Vaughn, her co-star in 2006's The Break-Up, Aniston has been linked to model Paul Sculfor and Sex and the City actor Jason Lewis.

However her desire to become a mother has eluded the Hollywood A-lister who is godmother to best friend, Courteney Cox's daughter Coco.

"I think the fact that both of them have been single for a couple of months is contributing to the chemistry they have on this film, even when they aren't shooting," the on-set source added.

"They genuinely enjoy each other's company.

"But if they're actually hooking up, they're doing it as quietly as possible."

Aniston may need all the moral support she can get when she comes face-to-face with Pitt and Jolie at next weekend's pre-Oscar charity party.

Eckhart, who was raised a Mormon, leaped to fame playing Julia Roberts' biker love interest in Erin Brokovich in 2000 and is soon to be seen playing Two-Face opposite the late Heath Ledger as The Joker in the new Batman movie The Dark Knight.

Meanwhile Jennifer celebrated her birthday on Wednesday night at the Los Angeles home of her friends Courteney Cox and David Arquette.

The low-key party was also attended by film producer Navine Narang, a mutual friend of Jennifer and the Arquettes.

Guests: David Arquette, right, hosted a surprise party for Jennifer at his and wife Courteney's Hollywood home. Film producer Navine Narang, a friend of Jennifer and the Arquettes, also attended

Birthday girl: Gifts arrive for Jennifer Aniston at friend Courteney Cox's home last night