Nunn joins Hibernian from the Turkish Women’s Super League side, Altay S.K Women having spent the first half of the season with the İzmir based side.
The 29-year-old has played in the England FA Women’s Championship having previously played for London City Lionesses and London Bees.
The winger also comes from the Arsenal Women’s set up that won the WSL in both 2011 and 2012, the Women’s FA Cup in 2010/11 and 2012/13, and the WSL cup in 2012 and 2013. Nunn was also included in the Gunner's Champions League squad in 2011.
Nunn spoke about joining the Hibees and said: “I am delighted to be moving to Scotland at a time when the league is growing, becoming more competitive and exciting.
“Hibernian is a great club, and I cannot wait to put the shirt on, play for this team, and in front of the fans at Meadowbank.”
Head Coach Dean Gibson said: “I’m really excited to add Brooke to the group on a contract that is for the longer term. We are building something that will hopefully turn out to be special.
“We have been after Brooke for a while now. I tried to sign her back at the start of 2021 and finally, after almost two years we have got her!
“We have said for a number of months we need to improve in the final third and hopefully Brooke can add that little bit we have been missing. She’s technically very good, but also explosive. She also comes very a great deal of experience which again is something we were keen to add to the group.
“Brooke will add to an already talented attacking group of players we have in Crystal, Eilidh, Kirsty, Nor and Rosie at the top end of the pitch.”
