Christina Applegate has become an "honesty missile'" since being diagnosed with multiple sclerosis (MS)

In an extract from her memoir You With the Sad Eyes - published by the Guardian - she writes: " I've become an honesty missile. When your physical situation deteriorates, and your life shrinks to the size of a king-sized bed, suddenly all the things you thought were important shift, too.

"The truth clarifies, like a camera lens slowly focusing."

She later added: "For so much of my life, I've felt like the good underlies the bad, but something strange has happened to me, something I'm not used to.

"I won't lie any more, be the good girl, and say that any of this is a blessing ...

"All this has left me unable to be polite any more - it's boring and it takes too much energy. Being kind and loving and nurturing is beautiful, but to be polite is almost to lie. To be respectful is important, but there's something about that sweet politeness demanded of women that stinks of faking our true feelings."

It comes after Christina recently launched a new online platform for people living with the degenerative neurological condition - Next in MS - in order to provide others with the opportunity to share their experiences.

A message posted on the site reads: "Living with multiple sclerosis isn't easy. Christina Applegate has never been shy about that. She's been open about the pain, the fatigue, the frustration - even the parts that are difficult to say out loud.

"That's why Christina is starting a different conversation ... one where we can talk openly, ask tough questions, seek difficult answers, and navigate complex paths forward, together.

"As Christina begins the next chapter of her MS journey, she's inviting you to come along for the ride ... and she's not holding back."

You With the Sad Eyes: A Memoir by Christina Applegate is due for release on March 3.