Doyle, Presiding Judge. Following resentencing, co-defendants Blaise Harris and Christian Evans Hughes appeal from a trial court order denying their motions to vacate an illegal sentence on the ground that the resentencing was void.[1] For the following reasons, we vacate the resentencing orders and remand the cases for resentencing consistent with this opinion. “‘This appeal presents a question of law, which we review de novo.”[2] The record shows that in 2016, Harris and Hughes were each convicted of two counts of armed robbery (Counts 1 and 2) and other charges in connection with their robbery of restaurant employees. They were sentenced, in relevant part, to serve 10 years on Count 1 (armed robbery) and 20 years to serve 10 in confinement on Count 2 (armed robbery) with the sentences to be served consecutively. Harris and Hughes appealed their convictions and the denial of their motions for new trial, challenging the sufficiency of the evidence and claiming they received ineffective assistance of counsel, and we affirmed the convictions in a consolidated appeal.[3] In August 2019, Harris and Hughes filed extraordinary motions for new trial, arguing that Counts 1 and 2 should have merged for sentencing purposes because the acts constituted a single armed robbery. In its brief, the State conceded that Counts 1 and 2 should have merged, the sentences should be vacated, and Harris and Hughes should be resentenced. The trial court agreed that Count 2 was void because it should have merged into Count 1, and on October 17, 2019, the court entered an order to vacate the original sentences and resentence the defendants. In the new sentencing order, the trial court imposed a sentence of 20 years on Count 1, noted that Count 2 was void, and stated that the sentences remained the same on the other (assault) counts. Harris and Hughes filed motions to declare the new sentences illegal as to Count 1, arguing that they were void because the trial court could not legally increase their sentences on Count 1 after they began serving them and after this Court affirmed their convictions. The trial court denied the motions, and Harris and Hughes now appeal. Harris and Hughes contend that the trial court erred by denying their motion to declare the new sentences void because it lacked jurisdiction to impose an increased sentence on Count 1. We agree. “[I]n the multiplepunishment context, the Double Jeopardy Clause of the Fifth Amendment protects a defendant’s legitimate expectation of finality in his original sentence. But a convicted defendant . . . has neither a vested right to nor a reasonable expectation of finality as to a pronounced sentence which is null and void.”[4] It is well-settled that “[a] trial judge has the authority to correct a void sentence at any time, and a sentence is void if the court imposes punishment that the law does not allow.”[5] Here, therefore, “the trial court was authorized to correct the void sentence it previously imposed, including by resentencing [Harris and Hughes].”[6] The trial court had the discretion to decide which armed robbery count to vacate.[7] The question here, however, is whether the trial court, having elected to vacate Count 2, could increase Hughes’s and Harris’s sentence on Count 1, which was not void.[8] In Curry v. State,[9] the Supreme Court of Georgia explained that “[a] sentence which has been reduced to writing and signed by the judge may not be increased after the defendant has begun to serve that sentence. This limitation on the court’s sentencing authority stems from the double jeopardy provisions of our constitutions.”[10] The Supreme Court later clarified that holding, explaining that consistent with the United Supreme Court’s decision in United States v. DiFrancesco,[11] “a defendant may be resentenced after the original sentence has begun being served, so long as (a) such resentencing is allowed by law, and (b) the defendant has no reasonable expectation in the finality of the original sentence.”[12] “Generally speaking, Georgia law gives trial judges great discretion in imposing a sentence within statutory parameters.”[13] Nevertheless, “in the multiplepunishment context, the Double Jeopardy Clause of the Fifth Amendment protects a defendants legitimate expectation of finality in his original sentence.”[14] Here, Count 1 was not void. And Hughes and Harris had a legitimate expectation of finality in their sentence on that count, which they had already began to serve. Therefore, the trial court lacked jurisdiction to increase Hughes’s and Harris’s sentences on Count 1, and it erred by denying their motions to declare the new sentences illegal as to that count.[15] Accordingly, we vacate Harris’s and Hughes’s amended sentences imposed in 2019 on Counts 1 and 2 and remand the cases to the trial court for resentencing. Judgments vacated and cases remanded with direction. Reese and Brown, JJ., concur.