Hello
World No. 1 doubles pair Nikola Mektic and Mate Pavic beat Italian duo Fabio Fognini and Jannik Sinner to seal a 2-1 victory.
Their inclusion will complete a formidable field also featuring Alexander Zverev, Dominic Thiem and Grigor Dimitrov, with the first of four legs set to take place in Belgrade on June 13 and 14.
The 33-year-old has had a relatively stress-free time at the tournament so far, dropping just one set and getting a walkover in the second round.
Croatia will enter the history books as winners of the last final played in the traditional format before the 118-year-old team competition gets a major revamp.
Marin Cilic, the 2017 runner-up, suffered a shock 3-6, 1-6, 6-4, 7-6(3), 7-5 defeat by Argentine Guido Pella.