46-times capped left-back Gary Naysmith joins the Dons on a one-year deal from Sheffield Utd.
The 33-year-old had been training with the Dons and turned out in the pre-season friendly against St Pauli in Germany, which ended 1-1.
And the left-back clearly demonstrated that he has plenty left in the tank as Brown has moved quickly to snap him up.
Last week, Naysmith told RedWeb: "I believe in my ability but it is one thing believing in your ability and it is another showing the management team that you are worth a deal.
"Aberdeen have a good squad of players. There is experience with Jamie and Russell at the back and with Stephen and Gavin in midfield. There are also a lot of very good young players including my roommate for the week Ryan Fraser. He could be a very good player."
Naysmith, who has scored once for Scotland, last made an appearance in Scottish football in October 2000 when his Hearts side beat Motherwell 3-0 at Tynecastle.
The defender joins fellow new signings Niall McGinn and Johnny Hayes as summer recruits at Pittodrie.