Portsmouth have signed Enda Stevens on a two-year deal after the defender was released by Aston Villa.
The 24-year-old left-back played 32 games at Doncaster last season during a loan spell with the League One club.
He played only nine games for Villa after signing from Shamrock Rovers in 2012, while he also had loan spells with Northampton and Notts County.
"Enda brings a lot of quality and adds balance to the left-hand side," manager Paul Cook told the club website.
The Republic of Ireland under-21 international rejected other offers from League One clubs before opting to join Pompey.
"This was a no-brainer because of the size of the club and the manager's aspirations for it," he said.
"It's easy to forget that this is a League Two club when you walk around the place and hopefully we can start to move back up the divisions."