The sad news were confirmed by Alicia's rep in a statement, which revealed the pair decided to go their separate ways after being together for 20 years.
The Clueless star and her husband Christopher have one child together - six-year-old son Bear Blue Jarecki - who they will continue to co-parent together.
The statement, released to E! Online, read: 'They still deeply love and respect each other and remain very close friends but have mutually decided to separate after being together for 20 years. They have a son together who they will continue to co-parent.'
The pair tied the knot back in 2005, at a private lakeside estate in California. Before saying 'I do', Alicia and Christopher - the lead singer of group S.T.U.N. - dated for eight years, after meeting outside a cinema in 1997.
Ahead of welcoming her first child, Alicia, who first found fame in the iconic 90s film Clueless as Cher Horowitz, said she couldn't wait to become a mother.
'I've been wanting to have a baby since I was two years old – I'm destined to be a mother,' Alicia said before giving birth to Bear Blue in 2011.
The mum-of-one is currently having fun in Hawaii with her son, and has been keeping fans updated on her 'adventure'.
Sharing a selfie of the two, she wrote: 'Bear and I on our Hawaiian adventure. My sweet sweet love 💕'.
She later posted another picture of her son at the beach, after news of her split were announced, and made it clear she's having a really good time in her mother and son getaway.
So fun playing in the water with Bear. Swimming, boogie boarding and just savoring. Weâve been staying at my friendâs home while he is away. Driving around in his big truck was fun in the rain and mud. Bear and I played with this adorable little man we met on the beach with his beautiful mom. And somehow, even cleaning the kitchen (constantly) and doing laundry here is fun.
'So fun playing in the water with Bear. Swimming, boogie boarding and just savoring. We've been staying at my friend's home while he is away. Driving around in his big truck was fun in the rain and mud. Bear and I played with this adorable little man we met on the beach with his beautiful mom. And somehow, even cleaning the kitchen (constantly) and doing laundry here is fun', she wrote.