For today only, the insurer says it is calling on people across the country to say ‘Oh Yes’ to the things that make them happy.
In addition to the Facebook competition there is a birthday party event and personalised merchandise to give away.
Churchill Insurance, which was founded in 1989, has introduced today's celebration to mark its 25th anniversary.
Lucy Brooksbank, head of marketing at Churchill Insurance, said: "The Churchill mascot has been an integral part of the brand for years and will continue to inject fun into our brand personality and products for many more to come.
"Churchill has built up a dedicated following and we are really grateful for all the birthday wishes he has received. We have got some exciting things in store to celebrate this important milestone and we look forward to sharing these celebrations with Churchill’s loyal supporters."