Julia Roberts to star in her first TV series
Semple will write the mini-series herself, while Roberts`s own company Red Om Films will produce it.
Roberts has previously appeared as a guest star in such TV shows as Friends and Law & Order, but this will be her first lead role in a series.
Today Will Be Different tells the story of a woman named Eleanor Flood who makes plans to have the best day of her life, but wakes up to find a strange new future unfolding.
In a statement, Semple said: "I`m giddy that Eleanor Flood will be brought to life by Julia Roberts... This will be a fun ride!"
It has not yet been confirmed which network will broadcast the show.
Roberts won an Oscar for best actress in 2001 for her role in Erin Brockovich and has also starred in films including Notting Hill, Pretty Woman and Runaway Bride.