The 28-year-old last week turned down an offer to stay with Birmingham.

Berger, who had surgery to overcome thyroid cancer in November 2017, was named in last season's WSL PFA Team of the Year after returning in February.

"It's something new - I'm looking forward to playing with one of the best clubs in the world," she said.

Chelsea manager Emma Hayes told the club website: "She has the experience, pedigree and certainly the mentality to come in here and succeed and add to the glut of quality goalkeepers we have here."

After 11 games Chelsea are third in the WSL table, above Birmingham on goal difference.