Kyrgios is back in the Australian side, Hewitt naming Alex de Minaur, Jordan Thompson, John Millman and John Peers in a strong line-up to compete in Spain.

The Canberra star hasn't played for Australia in the past 18 months and was left out of the team to play a qualification tie in Adelaide earlier this year.

His non-selection in January came days after denying a rift with Hewitt following his round-one exit at the Australian Open.

But Hewitt said Kyrgios had been the ultimate team man and said he had been willing to do "whatever it takes" to get back into the Davis Cup side.

"That has even been the sacrifice over the last couple of weeks pulling out of tournaments [to get his body right]," Hewitt told reporters in Melbourne.

"After the Laver Cup he did have a shoulder/collarbone injury, which he is pretty much over now. But he felt if he kept playing that may jeopardise his chances of possibly playing Davis Cup.

"He called me at the time about that and we worked out that felt like the best situation. He comes in a little bit underdone with the matches, but fortunately he's a guy who can go out there and light it up when he needs to.

"With this format, there are a lot of unknowns. He's the kind of guy I think this format really suits."

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Kyrgios is currently serving a six-month probation period for his spectacular meltdown in Cincinnati in August and subsequently branding the ATP corrupt at the US Open.

But his suspended sentence only applies to the ATP Tour and not Davis Cup.

The dual grand slam quarter-finalist's availability is a major boost for Hewitt, who has named his strongest possible team on rankings.

The skipper was unable to find room for young gun Alexei Popyrin, who has enjoyed a phenomenal 2019 season, highlighted by runs to the third round at the Australian Open and US Open.

"[Kyrgios] didn't play in Austria last year more because of his body. He had issues at the start of this year and straight away I got a message: 'mate, I want to get back in the team'," Hewitt said.

"The great thing is he has a great relationship with all the players as well. It's kind of him wanting to be part of the team and doing the right things day in and day out. I spoke to Nick this morning and he's up and about.

"He's doing everything in his power to be as close to ready as possible. For me, I'd much rather have him on my team than against him.

"...Nick's a different character and I understand that. We're not going to always put everybody in the same box, either. I feel like I know Nick probably as well as anyone. On a Davis Cup court he's done absolutely everything I've needed in the past when he's been a part of the team. He hasn't put a foot wrong.

"There are a lot of things he does in a team environment that I actually think we see the best of him."

Australia have been pitted in Group D alongside Belgium and Colombia for the inaugural 18-team finals in Madrid from November 18-24.

Australia face Colombia on November 19 and Belgium the next day.

If they can top Group D, they will qualify for the quarter-finals and meet either the USA, Italy or Canada for a place in the semis.