Millward was keen to bring Mason back to England

The 22-year-old Wales international has struggled to claim a regular place in the Melbourne Storm line-up since leaving Super League for Australia two years ago.

Mason made just four appearances for the Storm although he was sidelined with a medial ligament injury for a spell last season.

"It's great to be linking up with a club like St Helens," he said. "I know some of the players here already and I'm looking forward to getting involved in training and playing.

"I learned a lot in Melbourne from working alongside the likes of Robbie Kearns and I'm excited at the opportunity here."

I'm a little bit nervous but I think it's going to be a good move for me Keith Mason

Mason will bolster a Saints pack weakened by the losses of Sonny Nickle, Vila Matautia, Peter Shiels and David Fairleigh over the past two seasons.

Coach Ian Millward said: "Prop forward is one of the specialist positions within the game and it's good to have Keith on board.

"I think he's the type of player who can take the ball up for us consistently and I'm looking forward to helping him develop his game."

Mason's signing comes a day after Saints, who have been deducted two points for a breach of the salary cap, confirmed the release of stand-off Tommy Martyn at the end of the season.