This might be the most hilarious Whatsapp exchange we've seen in a while.
So, in case you didn't know, today is actually National Sickie Day, the most popular day for someone to take a sick day in work.
It usually ties in perfectly with the Super Bowl, so anyone who stayed up too late can have an extra few hours in bed.
However it seems Twitter user Mark McLelland completely got his days mixed up, as he sent a text to his boss yesterday, thinking it was Monday:
When u wake up thinking it's Monday morning and text your gaffer wanting a day aff 😂 pic.twitter.com/Z3UAah2AY9— Mark McLelland (@Mark_McLelland) February 5, 2017
At least Mark could see the funny side to it. Hopefully his boss did as well!