Miley Cyrus penned a sweet message to her ''best friend'' Liam Hemsworth to mark his birthday.

The 'We Can't Stop' hitmaker uploaded a silly selfie of the pair to mark the actor's 27th birthday.

She wrote: ''Happiest birthday EVER to my favorite being EVER EVER EVER! You have been my best friend since the day we met..... I am beyond lucky to share sooooo animals with you!!! I love you @liamhemsworth (sic)''

And the 24-year-old singer is said to be incredibly ''happy'' with her engagement to Liam.

A source said: ''She is happy with how the relationship with Liam is going. She's adamant that she doesn't want to get divorced, so she wants to make sure when she eventually gets married it actually means forever.

''She wants to do some more movies in 2017 and would love to work with Liam. It could be a romantic thing, a comedy or something that they play as characters who hate each other.''

And Miley is said to be in no rush to get married as she's worried she's not ''marriage material''.

An insider added: ''She's dropping all these hints that she's not marriage material but he's not catching on at all.

''While Miley may love him, if they don't get on the same page soon, it'll only end in heartbreak for him.''

The couple began dating in 2009 when they met on the set of their movie 'The Last Song' before getting engaged three years later. However, things didn't go to plan and they split for a while. Rumours of a new romance began again in 2016 when they were spotted together.

Meanwhile, Liam spent Christmas with Miley's family including her siblings Brandi, Trace, Noah and Braison as well as her mother Tish and father Billy.

Uploading a picture of the festivities at the time, Brandi said: ''Cyrus fam Christmas in full swing (sic)''