Miranda Lambert thinks she has a ''resting bitch face.''

The 33-year-old country music star has joked that she's rarely approached by fans when she's out and about in Nashville, Tennessee, because she is convinced she usually has - unintentionally - a sour expression plastered across her face.

Speaking on 'The Bobby Bones Show', she explained why she's never been hassled by fans: ''I kind of have this RBF [resting bitch face]. I don't mean to though I just do my thing, drink Miller Light, and hang out with some of my friends.''

However, one person the blonde beauty doesn't screw her face up at is her boyfriend Anderson East, who she's been dating for over a year, as she recently praised him for being so ''supportive and kind'' throughout the duration of their romance thus far.

Sharing a photo of the pair from the Academy of Country Music Awards, the 'Vice' hitmaker wrote: ''My sweet handsome date. Thanks @andersoneast for being so supportive and kind. #bamaboy #backtothefarm #texasbama#blueeyes (sic)''

Miranda and Anderson, 28, struck up their relationship after the 'Over You' singer divorced Blake Shelton - who is now in a relationship with Gwen Stefani - in 2015.

And, although they haven't been together for that long, it looks like their romance is going from strength to strength as a close friend described them as pretty ''serious.''

The insider said earlier this month: ''Whenever they are together they act like two free spirits ... Miranda adores Anderson. They understand each other. Anderson has given Miranda this confidence she hasn't felt in some time. They are very supportive with each other and their careers.

''Anderson and Miranda are serious. They have met both sides of their families. Both their families love what they have. They seem like they are in such a great place. They spend so much time together. They are also very involved with Miranda's animals. That's a big part of her life and Anderson is a huge animal lover.''