They'll join captain Jim Courier's team for the March 4-6 matches against Australia.
Isner is the highest-ranked singles player on the United States team at No. 11 in the ATP World Tour rankings, and Sock isn't too far behind at No. 23.
Isner is also one of the tallest players on any tennis court. At 6'10", he creates a looming presence and a big target to beat around the net, which has helped him win 10 career titles.
While he doesn't have a Grand Slam title, he has performed well at those tournaments with a 48-31 record.
Sock is relatively new compared to his Davis Cup teammates. He turned pro in 2011 and has just one career title.
The Bryan twins are one of the best doubles pairs in the world. Bob is ranked fifth, while Mike is sixth in the ATP rankings. The two have been a force in doubles play for almost 15 years, as they were ranked No. 1 in the world back in 2003.
The U.S. will be looking for its first Davis Cup title since 2007 and its 33rd overall as the most successful country in the competition.
The Americans will be lining up against an Australia team that features Bernard Tomic, Nick Kyrgios, Sam Groth and John Peers in what has become a familiar matchup. Australia and the United States have played each other 45 times at the Davis Cup, with the U.S. leading the all-time series 25-20, per the AP.
The winner of this matchup will go on to face the winner of Belgium and Croatia in July.
Stats courtesy of ATPWorldTour.com.