United Kingdom, Feb. 1 -- Carly Pearce finds Kelsea Ballerini's success to be "surreal".

The 34-year-old singer feels "really proud" of her "best friend", having watched Kelsea go from being a virtual unknown within the business to becoming one of country music's biggest stars.

Carly told PEOPLE: "Kelsea and I have been friends for over ten years. I watched her when she had 200 or 300 people in a little club, and now she's selling out big arenas, so it was surreal."

Carly feels Kelsea, 31, deserves every bit of success that she's achieved.

Carly - who has won a host of awards during her own career, including a Grammy - said: "Nobody deserves it more. She's my best friend in this industry, so I'm really proud of her."

The 'Next Girl' ...