The British-born ballroom and Latin dancer and international coach had been heavily linked to the role in recent weeks, but she has now been officially unveiled as the new panellist.
Shirley will serve as Head Judge on the panel - just as Len did - and will have the casting vote in the dance-off.
She said in a statement: “I am so excited and over the moon to have been given this wonderful opportunity. I can’t wait to get in to the ballroom and be part of the incredible and respected judging panel.
“’Strictly’ is so loved by the British public, I have always been a massive fan. I just can’t wait!”
Shirley is one of the top and most decorated professional dancers in the world. She is three-time British Open To The World Latin American champion, 10-time United States Latin American champion, and multiple-times British National champion. By the age of 21, Shirley had won nearly every major title she competed in worldwide.
She retired from competitive dancing in 1996, and now works as an acclaimed and respected international coach to many top professional and amateur dancers.
Her son, Mark Ballas, is also one of the professional dancers on the US version of ‘Strictly’, ‘Dancing With The Stars’.
Shirley’s fellow judges all said they were looking forward to the expertise she will bring to the show, which enters its 15th series this year.
Darcey said: “I look forward to meeting Shirley and welcoming her to our ‘Strictly’ team. Her years of experience in ballroom and Latin dancing are impressive and I’m sure she will be a great addition to our judging panel.”
Craig said: “Fantastic news that Shirley will be joining me and the other judges on the panel. I look forward to working with her on the next series of ‘Strictly’!”
Bruno added: “I know Shirley well - she is an incredible Latin dancer and trainer and I am sure she will be a great addition to the ‘Strictly’ team.”
Len Goodman announced he would be stepping down from the panel ahead of the last series, and made his last live appearance during December’s final, where he was given an emotional send off.
‘Strictly Come Dancing’ returns to BBC One in the autumn.