The singer-turned-actress and the Gosford Park actor made the sad news public on Wednesday (23Mar16) by posting a statement on Facebook.
The couple was last spotted together when Billie supported Laurence at the press night performance of his play The Patriotic Traitor in London in February (16).
Billie and Laurence met in 2006, while starring in a play called Treats together, and on New Year's Eve (31Dec) in 2007, they tied the knot at the church of St Mary's in Easebourne, West Sussex, near their home.
Laurence previously gushed over his initial attraction to The Secret Diary of a Call Girl star, stating, "It absolutely happened when I met Bill. We were in a rehearsal room and I knew there and then she was the one for me."
The former couple cemented the union with matching tattoos following a "drunken lunch" during their honeymoon in Mexico.
Laurence's tattoo reads: "Mrs Fox 31st December 2007", while hers reads: "Mr Fox 31 December 2007".
Billie and Laurence have two sons together, Winston, seven, and Eugene, three.
She was previously married to British TV presenter Chris Evans. The couple wed in 2001 when she was 19 and Chris was 35. They split in 2004 and finalised their divorce in 2007, months before she exchanged vows with Laurence.
This was his first marriage.