Speaking with Spanish publication Marca, the former Tottenham defender - who's been a revelation for Diego Simeone's title-chasing LaLiga side this season - said Costa calls him 'Wayne Rooney' up to 10 times a day.
"He does it all the time, just for a laugh," Trippier said. "But it's Diego, I don't care. We all find it funny and I like that he always makes jokes. He calls me Rooney up to 10 times a day.
"I knew him from the Premier League and he's the funniest player I've ever played with.
"There's a great atmosphere here and everyone makes jokes, but Costa is the funniest."
Insights into Costa's funny side provide fans with a glimpse away from the agitated figure who stalks Atleti's forward line, aggravating opposing fans and players in equal measure with his fiery disposition.