Invermay's Jordan Charles Garcie, 20, is already serving a suspended jail term for an assault in July 2013.

Yesterday magistrate Tim Hill found that Garcie assaulted Triple J Unearthed musician Timothy Whybrow and a fan in Charles Street just one month later.

Mr Whybrow told a hearing in the Launceston Magistrates Court in April that he was knocked out with a single punch by a man he later identified as Garcie.

He was helped up by Rob Stojanov, a fan who recognised Mr Whybrow from his social media music videos.

Mr Whybrow suffered a fractured jaw and nose.

The court heard that Mr Stojanov then approached Garcie about the assault, but he too was punched to the ground.

He suffered a displaced nose requiring surgery and suffers ongoing breathing issues.

Following the assaults, Mr Whybrow surreptitiously filmed Garcie, apparently menacing another male, in order to identify him to police.

Mr Hill rejected a submission from lawyer Adrian Hall that there was a risk that Mr Whybrow was simply identifying the person in the video as the attacker.

The magistrate was scathing of defence witnesses Brett Delphine and Fletcher Gilham.

``Mr Delphine particularly gave me the impression that he had been given a basic scenario to relate and then had difficulty fleshing his story out,'' Mr Hill said.

``Mr Gilham had similar difficulties.''

Garcie was remanded on bail for sentence on July 4.

pbillings@examiner.com.au