West Ham United defender Kurt Zouma has pleaded guilty to kicking and slapping his pet cat in a video that also showed him saying "I swear I'll kill it".
The 27-year-old admitted two offences under the Animal Welfare Act at a hearing at Thames Magistrates' Court.
Zouma's brother Yoan, who plays for Dagenham and Redbridge, admitted one offence after an RSPCA investigation.
Yoan, 24, filmed the incident, which was posted on social media. Sentencing has been adjourned to 1 June.
The brothers' addresses were withheld following a court order.
The court was told about disturbing footage of the incident, which was filmed at the West Ham player's home and posted on Snapchat by his brother on 6 February.
It was later seen by a woman who had been messaging Yoan, and she raised concern.
Zouma could be seen volleying the Bengal cat across his kitchen, before throwing a pair of shoes at it and slapping its head.
Prosecutor Hazel Stevens told the court that Kurt could be heard saying: "I swear I'll kill it, I swear I'll kill it."
He admitted two counts of causing unnecessary suffering to a protected animal.
Yoan admitted one count of aiding, abetting, counselling or procuring his older brother to commit an offence.