Former QPR, Aldershot Town, Wycombe Wanderers and Oxford United boss Gary Waddock has been appointed assistant manager at Portsmouth.
"Pompey are a big club and I want to help them start to move forwards again," said Waddock.
"I'm excited to be working with Andy, the staff and the players"
He added: "I've worked at this level before, so know what is required and now I can't wait to get started.
"I'd like to thank the manager and chairman at Barnet for their help in allowing me to move here."
Waddock spent time at QPR, Millwall, Bristol Rovers and Luton Town during his playing days and represented the Republic of Ireland at international level.
He has enjoyed some success in management, leading Aldershot to the Conference title in 2008 and Wycombe to promotion to League One in 2011.