O'Brien, left, has agreed a deal to switch from Stirling Albion and is desperate to make the grade in full-time football after a disappointing couple of seasons with Dundee.
He told the Telegraph: "It's exciting I'm going to be working with Allan again, as I've known him since I was 18.
"I was in the youth team when he came to Stirling Albion and he taught me how to play the wide position, as he was a winger himself.
"I enjoy his style of football. He likes to get the ball wide and get crosses into the box. He's a very lively, bubbly character but it's not just about his personality - his sessions are excellent.
"A lot of his training exercises are based around passing, crossing and finishing. He has just got something about him.
"I can remember playing against Morton in the Second Division and the crowds they got were unbelievable.
"They could be a big club but that all depends on performances on the park. If we are doing well, we will get more and more fans. "
O'Brien, 26, came through the ranks at Stirling before being signed by Alex Rae for Dundee in 2007. But things fizzled out after a promising start.
He said: "I started well when I scored a couple in pre-season and the winner against Clyde in my first start.
"Straight after that I went in for a hernia operation and that was me until after Christmas. I played a handful of games at the end of the season.
"At the start of my second season, I was in the team and doing well then Alex Rae was sacked and Jocky Scott came in.
"I stayed in the team for a bit but then Jocky brought in Georgios Efrem from Rangers and I didn't get much of a chance after that.
"Maybe the manager didn't believe in me and when you don't play many games it knocks your confidence.
"When I came back to Stirling from Dundee I wasn't thinking about going full-time again. This will probably be my last shot so I want to give it my best."