Ouattara joins the Bees for a club record £42.5m and has signed a deal to 2030.
Andrews said: “We’re really happy to get Dango in. He’s someone that we were aware and surprised could be available and, once we knew that signing him might be a possibility, we really focused on trying to get him in.
“We liked his Premier League experience, even at his young age, and he just hasn’t found the rhythm yet because of a lack of consistent game time.
“He also suits the way we want to play - he has something that we were lacking in the forward line, and he will complement what we already have in the building.
“The fans will love him; he’s the type of player that they will get off their seat for.”
Replacement for Mbeumo
Bees football chief Phil Giles also said: “Having sold Bryan Mbeumo, we have been looking to add an attacking player to the squad, and we think Dango is the perfect addition.
“It’s been well documented that there has been more change over this summer than in recent years at the club; however, I’m very confident that, in each case where a player has left us, we have managed to bring in an extremely strong replacement, and Dango is the latest example of that.
“We also have players such as Aaron Hickey, Rico Henry and Igor Thiago who are fit and ready, and also players such as Frank Onyeka who have benefitted from a loan last season, so I think the squad is looking very strong.
“I’m really excited to see Dango on the pitch and bringing his unique skillset to the team.”