These customers will be able to enjoy free refills on hot brewed or iced coffee, or hot or iced tea during their visit. Starbucks says folks must have their first beverage served in a ceramic mug, glass or personal cup — no disposable vessels — to receive free refills.

Starbucks fans can now get free refills for some drinks — but not all. The coffee chain is also bringing back its self-serve milk and sweeteners bar.

Starbucks has reported better-than-expected sales in its fiscal first quarter as some of its turnaround efforts start to take hold.

Starbucks reported a smaller-than-expected fall in first-quarter comparable sales on Tuesday, indicating early signs of success for CEO Brian Niccol's turnaround efforts for the coffee chain battling sluggish demand.

Chairman and CEO Brian Niccol, who joined the company in September, said customer-focused changes - such as a decision to stop charging extra for non-dairy milk and a streamlining of the menu - were helping to improve service and drive store traffic.