Kerber and Beltz had their first stint in 2011, splitting in 2013 before teaming up again for 2015, a year before the German would win her first two Grand Slam titles. But they split following a subpar 2017 season, after which Kerber joined coach Wim Fissette, and she then won another major. Yet they also abruptly split just before the 2018 season finished. Kerber has since worked with another three coaches but hasn't found similar success.
Beltz had been coaching Donna Vekic. They decided to stop their collaboration during the tour suspension. Kerber, a former No. 1, has 12 career titles.
Meanwhile, Johanna Konta has a new coach, Thomas Hogstedt, as she trains for a return to tour.
The 29-year-old has split with Dimitri Zavialoff, according to the Daily Mail, which said it was mutually agreed because the coach could not keep his travel requirements under current conditions.
Hogstedt has worked with several WTA players, including Maria Sharapova, Caroline Wozniacki and Eugenie Bouchard.
Konta had entered the WTA clay-court event in Palermo next week, the first on the schedule since tour competition was suspended more than five months ago. But she has indicated that she could now withdraw, choosing instead to practice before playing some events on hard-courts before the US Open.
She will compete in a British team exhibition this week in Roehampton, organized by Jamie Murray.
Who will remain in this year's 21 & Under Club, and which new players will join them?
Find out all week on TENNIS.com and Baseline.
Monday, July 27: Sofia Kenin | Monday, July 27: Elena Rybakina | Monday, July 27: Alex de Minaur, Dayana Yastremska, Casper Ruud | Tuesday, July 28: Stefanos Tsitsipas | Tuesday, July 28: Thiago Seyboth Wild