Today is Kim Kardashian's birthday – and you'll never guess why she's spending it wearing a hospital gown!

The reality TV star is actually at the hospital playing nursemaid -- her main squeeze, football star Reggie Bush, is recovering from knee surgery and Kim is there to attend to his every need. She writes today in a new blog, "I was supposed to be in London right now with Reggie but we had to cancel our trip. … In [Sunday's] game against the Carolina Panthers, Reggie injured his left knee and needed surgery. When I saw him limp off the field my heart dropped!"

She writes that Reggie underwent surgery, and now: "All that has mattered is that Reggie is going to be okay! … He's pretty bummed that the special birthday he planned in London couldn't happen, but as long as he is okay, I will have the best birthday ever!!!!"