The 38-year-old started his senior career at Cowdenbeath in 2003, turning out 13 times for the Blue Brazil before making the move to Kelty Hearts in 2005.
After nine years at New Central Park, Fleming made the move to Bayview in the summer of 2014, making 36 appearances for the club, as the Fifers finished fourth in League Two before losing to Stenhousemuir in the play-offs.
Next up was a move to Arbroath for season 2015-16 before joining Montrose the following season, where he helped guide them to the League Two title in 2017-18 by keeping 18 clean sheets.
Fleming left Links Park after six seasons and 157 appearances, most recently both Montrose’s Championship play-off semi-final ties against Airdrieonians.
"Allan will come in and add healthy competition with Jude Smith and Scott Gallacher for the goalkeeper jersey in our starting 11, as well as helping to develop Jude as a player both on and off the pitch.
"Unfortunately, Scott is still waiting on an operation to the finger he injured during the warm-up against Peterhead back in January, so I’d like to thank the chairman and the board for allowing us to bring Allan in.”
Fleming, who will join up with the squad when they return to training next month, was praised by Montrose boss Stewart Petrie, who reckoned he’ll be well remembered for those 18 shutouts on the way to League 2 title success, featuring in the SPFL Team of the Year and making Montrose’s team of the decade.
“Allan has been a key player during my time here and will undoubtedly enter the club’s Hall of Fame in due course for his outstanding contribution to our league win,” said Petrie.