Chelsea have announced the £10.5million transfer of David Datro Fofana from Molde.
And the Ivorian's contract lasts until 2029 with the option of a further 12 months.
The Blues announced the transfer at the end of December after agreeing the deal with the Norwegian side.
But now it is all done and Fofana has signed on the dotted line and posed for the customary photos.
The striker, 20, said: "Hello dear fans, I'm here.
"I've arrived well and I'm very happy to sign for the club of my dreams.
"I'll see you soon on the pitch, cheers!"