¶1Defendant, Scott Perry, was convicted, after a jury trial, of possession of heroin, a controlled substance. He was sentenced to imprisonment for five years.
¶2On August 23, 1998, two officers were on patrol in the City of St. Louis when a woman informed them she had seen two men sitting in a truck at an intersection for approximately twenty minutes. The officers then proceeded to the intersection, pulled up behind the truck and activated their lights. Immediately, Defendant exited the driver’s side of the truck and walked toward the police car. One officer instructed him to return to the automobile. The police then saw him throw down a cigarette box, which later proved to contain marijuana and three pills of heroin. Defendant was then arrested and placed in the patrol car.
¶3The officer then approached the passenger side of the vehicle and located a marijuana cigarette tucked behind the ear of the passenger, Carlton Roberts. Roberts *398was then arrested and placed in the patrol car.
¶4Defendant did not testify at trial. He did, however, present the testimony of Carlton Roberts who testified that both the heroin and marijuana cigarette were his. Roberts further testified that he and Defendant were only in the car for a few minutes when the police vehicle approached, and that when the police ear arrived, he got out of the car and threw the box containing the marijuana and heroin on the seat where it was later found by the police.
¶5We first address Defendant’s second point because it is dispositive of this appeal. Defendant contends that the trial court’s submission to the jury of Instruction No. 5, the verdict director, was error because it was not supported by the evidence. The State concedes the trial court erred in submitting the instruction, but argues that Defendant suffered no prejudice.
¶6At the close of the evidence, the State offered, and the trial court gave, over objection of Defendant, the following instruction:
¶7If you find and believe from the evidence beyond a reasonable doubt:
First, that on August 23, 1998, in the City of St. Louis, State of Missouri, the defendant possessed heroin, a controlled substance, and
Second, that defendant knew of its presence and illegal nature,
then you will find the defendant guilty of possessing a controlled substance.
However, unless you find and believe from the evidence beyond a reasonable doubt each and all of these propositions, you must find the defendant not guilty of that offense.
As used in this instruction, the term “possessed” means either actual or constructive possession of the substance. A person has actual possession if he has the substance on his person or within easy reach and convenient control. A person who is not in actual possession has constructive possession if he has the power and intention at a given time to exercise dominion or control over the substance either directly or through another person or persons. Possession may be sole or joint. If one person alone has possession of a substance, possession is sole. If hvo or more persons share possession of a substance, possession is joint.
¶8(emphasis added).
¶9Instructions must be based on substantial evidence and reasonable inferences drawn therefrom. State v. Brown, 958 S.W.2d 574, 580 (Mo.App.W.D.1997); State v. Price, 684 S.W.2d 566, 568 (Mo. App.1984). An appellate court will reverse for instructional error only if there is both error in submitting the instruction and prejudice to the defendant. State v. Taylor, 944 S.W.2d 925, 936 (Mo. banc 1997). When instructional error arises, prejudice is judicially determined by considering the facts and instruction together. Brown, 958 S.W.2d at 581.
¶10Instruction No. 5 tracks the language of MAI-CR 3d 325.02. The above underlined portion is included in section 325.02 but is shown as a parenthetical addition. Although the Notes on Use to this section offer no guidance on when this parenthetical is to be used, MAI-CR 3d 333.00(3) provides that “no definition submitted to a jury should contain portions not applicable to the facts of the particular case.”
¶11In this case, the disjunctive submission which allowed the jury to find joint possession was clearly error, as the State concedes, because there was insufficient evidence produced at trial to sustain a finding of joint possession. To the contrary, the evidence produced at trial could only support a finding that Defendant alone, or Roberts alone had sole possession of the drugs.
¶12The State argues however, that Defendant was not prejudiced because the joint *399possession language was “mere surplus-age.” The State claims the instruction contained each element required to sustain a conviction of possession of a controlled substance and the State proved each of these elements. We disagree.
¶13“Instructions must be based on substantial evidence and reasonable inferences therefrom.” Price, 684 S.W.2d at 568. Here, the jury was permitted, via Instruction No. 5, to consider joint possession in their determination of guilt. This allowed the jury to convict Defendant upon a determination that -he somehow knew about the drugs or that he and Roberts shared the drugs. Because neither the State’s theory nor the Defendant’s theory of the case could support such a determination, it would be based on speculation and conjecture.
¶14The prejudice to Defendant is illustrated by closing argument in which the State emphasized the verdict directing instructions. The prosecutor argued “Joint and sole possession. Let’s just say possibly Carlton Roberts first had or maybe it’s Carlton Roberts’ and Scott Perry’s drugs. That’s joint possession.” Thus, the instruction allowed the prosecutor to argue a theory of the case not supported by the evidence, thereby lessening the State’s burden of proof. Defendant’s second point is granted.
¶15In view of our disposition on point two, we need not address Defendant’s first point claiming trial court error in failing to grant his request for a mistrial.
¶16We reverse and remand.
¶17. The record is unclear whether defendant was sentenced as a prior offender, a prior and persistent offender, or a prior and persistent and a prior drug offender.