Stephens, 19, stunned Serena Williams in the quarter-finals of the Australian Open, the youngest American to go so deep in a Grand Slam event since Williams in 2000 at Wimbledon.
Stephens, now up to a career-high of 19 in the world rankings, made her Fed Cup debut in doubles last year in a World Group play-off against Ukraine.
She is expected to make her singles debut in what could be a tough tie on the red clay of Rimini on February 9-10.
Also named to the US squad were first-time Fed Cup players Varvara Lepchenko and Jamie Hampton, 23, plus veteran doubles specialist Liezel Huber.
Uzbekistan-born Lepchenko, 26, became a US citizen last September.
Captain Mary-Joe Fernandez said: "I am excited to welcome some new, young players to the US Fed Cup team.
"Italy is a championship team and always plays well in Fed Cup competition, but I have confidence in the players on this team and know that they will all be ready to compete hard."
Italy defeated the Americans in the 2009 and 2010 Fed Cup finals after losing their first nine Fed Cup meetings.
The Italian squad features World No 7 Sara Errani and World No 16 Roberta Vinci, who are not only clay court specialists but they combined to win the women's doubles title at the Australian Open.