The former Chelsea striker formally completed his move away from Stamford Bridge back to Atletico Madrid this week and he has been wearing the red and white kit for the first time since his return.
His excitement is clear as he was quick to post a picture of his shorts, bearing the club crest, onto his Instagram story.
Diego Costa on Instagram pic.twitter.com/sKvhG9ms87
— Socabol Football (@Socabol) September 27, 2017
The post comes on the same day his new club face his former club in the Champions League and less than 24 hours after he uploaded an emotional message on his Instagram page, thanking the Chelsea fans for their support during his spell at Stamford Bridge.
Costa will first join Atletico on a loan deal until the end of the season before signing for a fee of £58m next summer. He won't be able to play at the new Wanda Metropolitano stadium until January, though, as Simeone's side are currently under a transfer ban.