Millar had a brief loan spell with English League One side Shrewsbury Town in 2020-2021, where he scored a goal in nine first-team appearances, but the move was marred by a hamstring injury and contracting Covid-19.

The right back returned to the Jets in January for the 2021 A-League campaign, but this week headed back abroad and signed a one-year deal with Scottish outfit St Mirren.

Millar admitted it was a difficult decision to leave Newcastle, but he is determined to make his mark in Britiain.

"I loved my time in the UK with Shrewsbury and there was a couple of offers in England again, but to play in the top league in Scotland against massive and quality opposition was something I couldn't turn down," he told FTBL.

"St Mirren is a well-established Scottish Premiership side with great aspirations. They had a great year last year and went on a great cup run, so the quality of the team was there.

"And then speaking to the gaffer, hearing that he is really excited to get you in, was another reason wanting to come.

"Yeah exactly [it feels like unfinished business overseas], picking up the injury early on and not being able to agree on a deal with the Jets I just felt like I had another couple of levels to get to."

Millar started his career with Melbourne City and has had stints with Dandenong Thunder, South Melbourne, Central Coast and the Jets. 

The 25-year-old played 41 games for Newcastle and said he enjoyed his time in the Hunter region.

"I loved Newcastle, I ended up buying a house there because we loved the area," he said.

"It was also tough because I made some really good friends there too. But it was exciting for a new challenge."

Millar landed in Scotland on Sunday and started training with his new team on Monday.

"The club's set-up is class, it's a good stadium and good training facilities."

Paisley-based St Mirren are currently second from bottom in Scotland with two draws and two defeats from their first four league matches.

The Buddies are managed by Irishman Jim Goodwin and face Dundee United this weekend.