Sir Lewis Hamilton's dog Roscoe has been put into a coma

Lewis - who is often seen with Roscoe during Formula One race weekends - wrote on Instagram: "Please keep Roscoe in your thoughts. I want to keep you all updated. Roscoe caught pneumonia again and was struggling to breathe. He was admitted into hospital and sedated to calm him while they did checks on him and during the process his heart stopped. They managed to get a heartbeat back and now he's in a coma. We don't know whether he will wake from this. Tomorrow we'll try to wake him up. I'm by his side and want to thank you all for your prayers and support."

Lewis' posts also features photos of himself kissing Roscoe - who has his own Instagram account with more than one million followers - on his head.

Lewis previously expressed concern for Roscoe back in May, when he admitted to feeling anxious about the health of his dog.

The sports star said at the time: "He's 12-and-a-half years old so he's an old boy.

"He had pneumonia, but he's fine now. But definitely this is a time where every time I get a text message from the lady who's looking after him, my heart stops for a second. You know, what's next?"

Lewis acknowledged that Roscoe has begun to feel more lethargic in recent times. However, he hoped to lift his spirits by taking him with him to the British Grand Prix in July.

The sporting icon said: "I really want to try and bring him to Silverstone [in July] and take him to Monza [in September] and cheer him up.

"I was with him before Miami [the race before Imola]. He still wants to play. He still has that kind of spirit but he sleeps a lot."