The 33-year-old Ghana captain was without a club following his exit from Qatari outfit Al Sadd and has signed a deal until the end of the season. Ayew is understood to have turned down the chance to join Premier League rivals Everton in order to head to the City Ground. Ayew becomes Forest's 29th signing since winning promotion back to the Premier League last May, with the midlands club adding three players to their ranks on Tuesday's transfer deadline day as Felipe, Jonjo Shelvey and Keylor Navas all joined.
The 33-year-old was without a club following his exit from Qatari outfit Al Sadd.
Chelsea has spent $300 million in each of the last two transfer windows as it attempts to overhaul its squad.