The cashier who accepted a fake $20 note from George Floyd has described him as being “friendly” and “approachable” shortly before a white police officer pinned the black man to the ground.

The jury in Derek Chauvin’s murder trial was also played never-before-seen security camera footage showing Mr Floyd to be smiling and energetic inside the shop.

Cashier Christopher Martin, 19, said he made conversation with Mr Floyd, asking him if he played baseball.

“It kind of took him a little long to get to what he was trying to say, so it would appear that he was high [on drugs],” Mr Martin said.

He said Mr Floyd eventually replied to him, saying that he played football.

Mr Floyd even became “talkative” and had no problems holding the conversation, said Mr Martin.

The teenager was one of the last people to speak with Mr Floyd before the older man’s deadly arrest last May.

“He seemed to just be having an average Memorial Day, just living his life,” Mr Martin said of the 46-year-old, adding that he seemed “very friendly” and “approachable”.

Mr Martin said he wishes police had never been called. Photo: AAP

Soon after, Martin, 19, sold him a pack of cigarettes.

The worker said he told the jury he thought the note was counterfeit and considered just letting the shop deduct it from his wages.

“When I saw the bill I noticed that it had a blue pigment to it, kind of like a $100 bill would have,” Mr Martin said, adding that he “found that odd” and “assumed it was fake”.

He then decided to tell his manager, who told Mr Martin to get Mr Floyd, who had already left the shop, to come back in.

“I offered to pay but he [the manager] said no, just get him [Mr Floyd] to come back inside,” Mr Martin testified.

When some of his coworkers failed to get Mr Floyd back in the shop, his manager told an employee to call 911 about the suspected fake bill, he said.

The events which followed would spark worldwide outrage over racism at the hands of police.

Chauvin, who is white, was fired by the city’s police department the day after he was captured on video with his knee on the neck of Mr Floyd.

He has pleaded not guilty to murder and manslaughter charges.

“If I had not taken the bill, this could’ve been avoided,” Mr Martin said.

The jury watched a security camera video that showed a cheerful-looking Mr Floyd in his final minutes inside the shop before he ended up below Chauvin on the road outside.

Mr Floyd appeared cheerful in surveillance footage. Photo: AAP

The silent video played for the jury showed Mr Floyd dressed in a black tank top approaching Cup Food’s counter with a banana in hand.

He could be seen smiling and putting his arm around a female friend.

Mr Floyd appeared to be constantly in motion. Shifting his weight from one foot to the other, it looked as if he was about to start dancing.

Several eyewitnesses, one a child of nine, have spent the last two days describing to the jury the shock of watching Mr Floyd’s dying struggle beneath Chauvin.

He was pinned for more than nine minutes while screaming “I can’t breathe”.

The trial continues.