Defender moves to Fratton Park in a one-month dealPaul Robinson has joined Portsmouth on a one-month loan deal.
The 32-year-old, who has made 360 Millwall appearances and had a testimonial last year, has completed formalities on the temporary switch and will travel down to the south coast to train with his new team-mates for the first time on Thursday.
Robbo could be in line to make his debut for the League Two club in their season opener away to Exeter on Saturday, after which they face a Capital One Cup tie against Peterborough before returning to League action with further August fixtures against Cambridge, Northampton, Oxford and Newport.
"It's a good chance for me to go and get some games under my belt," Robbo told millwallfc.co.uk. "Portsmouth are a massive club and the chance to play so many games in 28 days was too big an opportunity to resist.
"Hopefully I can go there to improve my match sharpness and help a big club on its path to getting back to where it belongs."