Stars of the WTA Tour including Simona Halep, Ashleigh Barty and Angelique Kerber scatter across the globe this week and don their country's colors as Fed Cup play gets under way, with a spot in this year's final at stake for four teams.

Below is your guide to who is playing where in April's Fed Cup semifinals and play-offs.

SEMIFINALS

France vs Romania, Rouen (indoor clay)

The Romanian team pulled off one of the biggest shocks of the first round in February when they ousted defending champions the Czech Republic on their home turf in Ostrava, with Irina-Camelia Begu and Monica Niculescu squeaking through a thrilling deciding doubles rubber. Led once again by World No.2 Simona Halep, Romania - in the semifinals for the first time since 1973 - must navigate another away tie to reach their first ever Fed Cup final, against the formidable two-time champions France.

FRA: Caroline Garcia, Pauline Parmentier, Alizé Cornet, Kristina Mladenovic (captain: Julien Benneteau)

ROU: Simona Halep, Mihaela Buzarnescu, Irina-Camelia Begu, Monica Niculescu, Raluca Olaru (captain: Florin Segarceanu)

Australia vs Belarus, Brisbane (outdoor hard)

Historically, Australia are one of the Fed Cup's most accomplished teams, having lifted the trophy seven times between 1964 and 1974. But it's very much historically: they have not made the final since 1993, and this is just their second semifinal since then. Furthermore, they come up against one of the competition's newest upstarts: Belarus stunned the world with a series of upsets in 2017 to reach the final, despite their greatest ever player - Victoria Azarenka - being on maternity leave. Nonetheless, Australia couldn't have chosen anyone in better form to revive their fortunes than newly crowned Miami champion Ashleigh Barty - while for the first time, Belarus will field a team that includes Azarenka alongside 2017 heroines Aryna Sabalenka and Aliaksandra Sasnovich in what's sure to be a barnburner of a tie.

AUS: Ashleigh Barty, Daria Gavrilova, Samantha Stosur, Priscilla Hon (captain: Alicia Molik)

BLR: Aryna Sabalenka, Aliaksandra Sasnovich, Victoria Azarenka, Vera Lapko, Lidziya Marozava (captain: Tatiana Poutchek)

WORLD GROUP PLAY-OFFS

Czech Republic vs Canada, Prostejov (indoor clay)

Eleven-time champions the Czech Republic have not competed outside the World Group since 2008; Canada, by contrast, have only competed inside it once since then, in 2015. Their clash in the play-offs is the result of the Czechs' upset at the hands of Romania, while Canada - led by Bianca Andreescu, one month before she announced herself to the world with the Indian Wells title - whitewashed the Netherlands to rise out of World Group II. However, neither Andreescu nor Czech No.1 Karolina Pliskova will be present; instead, last year's champions will be led by 19-year-old Indian Wells and Miami quarterfinalist Marketa Vondrousova at home in Prostejov, while Canada will rely on former World No.38 Rebecca Marino and Australian Open girls' runner-up Leylah Fernandez.

CZE: Marketa Vondrousova, Karolina Muchova, Marie Bouzkova, Lucie Safarova, Barbora Krejcikova (captain: Petr Pala)

CAN: Rebecca Marino, Leylah Fernandez, Gabriela Dabrowski, Sharon Fichman (captain: Heidi El Tabakh)

USA vs Switzerland, San Antonio (indoor hard)

It wasn't just the defending champions who fell at the first hurdle this year: 2018 finalists the USA were also knocked out at home at the hands of Australia. The Americans have another home tie opportunity to retain their position in the World Group, and will field World No.8 Sloane Stephens and newly crowned Charleston champion Madison Keys against 1998 runners-up Switzerland, who will be without Dubai champion Belinda Bencic but will be led by Viktorija Golubic and Timea Bacsinszky.

USA: Sloane Stephens, Madison Keys, Sofia Kenin, Jessica Pegula, Jennifer Brady (captain: Kathy Rinaldi)

SUI: Viktorija Golubic, Timea Bacsinszky, Conny Perrin, Ylena In-Albon (captain: Heinz Guenthardt)

GALLERY: Wonderful world: Keys, Pliskova, Halep, Garcia and more in Fed Cup action

Latvia vs Germany, Riga (indoor hard)

Latvia's first ever Fed Cup home tie in February was a resounding success: a full-strength team, led by Anastasija Sevastova and Jelena Ostapenko, whitewashed Slovakia to put a place in the World Group within touching distance. They'll seek to repeat the feat against two-time champions Germany, who have not fallen out of the World Group in six years - and who will field a full-strength team of their own, featuring three-time Grand Slam champion Angelique Kerber, in a bid to cling on.

LAT: Anastasija Sevastova, Jelena Ostapenko, Diana Marcinkevica, Daniela Vismane, Patricija Spaka (captain: Adrians Zguns)

GER: Angelique Kerber, Julia Goerges, Andrea Petkovic, Anna-Lena Groenefeld (captain: Jens Gerlach)

Belgium vs Spain, Kortrijk (indoor hard)

Fast indoor hard courts aren't what most people would associate with Spanish success - but with big-serving Georgina Garcia Perez at the helm, five-time champions Team España managed to edge Japan away in Kita-kyushu to move a step closer to returning to the World Group. Garcia Perez is back, naturally, while Monterrey champion Garbiñe Muguruza also rejoins the team - but they'll face indoor specialists on their home turf in Belgium, whose leading singles players Alison Van Uytvanck and Kirsten Flipkens have won a combined four titles indoors.

BEL: Alison Van Uytvanck, Kirsten Flipkens, Ysaline Bonaventure, Yanina Wickmayer (captain: Johan Van Herck)

ESP: Garbiñe Muguruza, Carla Suárez Navarro, Aliona Bolsova, Georgina Garcia Perez, María José Martínez Sánchez (captain: Anabel Medina Garrigues)

WORLD GROUP II PLAY-OFFS

Russia vs Italy, Moscow (indoor clay)

Two Fed Cup colossi will clash at a level neither team is used to: four-time champions Russia suffered the indignity of relegation to zonal ties for the first time since 1997 last year and were forced to extricate themselves from the Euro-Africa group stages in February, while four-time champions Italy will battle to avoid the same fate for the first time since 1997. These bifs to regain former glories make this tie one of the weekend's most fascinating - particularly with both teams offering a blend of youth and experience and, in Anastasia Pavlyuchenkova and Sara Errani, two players who have both competed in the Fed Cup final.

RUS: Daria Kasatkina, Anastasia Pavlyuchenkova, Anastasia Potapova, Natalia Vikhlyantseva, Vlada Koval (captain: Igor Andreev)

ITA: Camila Giorgi, Martina Trevisan, Jasmine Paolini, Sara Errani (captain: Tathiana Garbin)

Japan vs Netherlands, Osaka (outdoor hard)

1996 semifinalists Japan gained World Group II status for the first time in five years last year, and will bid to retain it with a home tie against the Netherlands, who have not dipped to the group stages since 2014. Neither team, however, features their leading player, with Naomi Osaka and Kiki Bertens both out of action.

JPN: Misaki Doi, Nao Hibino, Kurumi Nara, Eri Hozumi, Shuko Aoyama (captain: Toshihisa Tsuchihashi)

NED: Richel Hogenkamp, Bibiane Schoofs, Lesley Kerkhove, Demi Schuurs (captain: Paul Haarhuis)

Great Britain vs Kazakhstan, London (indoor hard)

For over two-and-a-half decades, Great Britain's Fed Cup narrative has been one of frustration, having spent every year since 1993 in the group stages and losing play-offs to join World Group II in 2012, 2013 and 2017. For the first time, though, the British team will host one of those play-offs - and it's sure to be one of the most exciting ties of the weekend as the same team, led by Johanna Konta, who put together an impeccable group record in front of their home crowd in Bath in February host the dynamic Kazakh cohort of Yulia Putintseva and Zarina Diyas. For their part, Kazakhstan are also seeking to make history by joining World Group II for the first time.

GBR: Johanna Konta, Katie Boulter, Heather Watson, Harriet Dart, Katie Swan (captain: Anne Keothavong)

KAZ: Yulia Putintseva, Zarina Diyas, Anna Danilina, Galina Voskoboeva (captain: Dias Doskarayev)

Slovakia vs Brazil, Bratislava (indoor clay)

2002 champions Slovakia have not fallen to the group stages since 2006 - and will bid to avoid that fate against Brazil, who are seeking to rise out of the group stages for the first time since 1992. The Slovaks will field a full-strength team that includes former WTA Finals champion Dominika Cibulkova and rising youngster Viktoria Kuzmova, while Beatriz Haddad Maia's comeback from a back injury will continue for Brazil.

SVK: Dominika Cibulkova, Viktoria Kuzmova, Anna Karolina Schmiedlova, Magdalena Rybarikova, Rebecca Sramkova (captain: Matej Lipak)

BRA: Beatriz Haddad Maia, Carolina Alves, Gabriela Ce, Luisa Stefani, Thaisa Grana Pedretti (captain: Roberta Burzagli)