Tim Walz is 'nervous' about upcoming debate as he hunkers down with surprise candidate playing J.D. Vance

Tim Walz is 'nervous' about facing J.D. Vance in next week's vice presidential debate as he hunkers down this weekend to prepare for Tuesday's showdown.

The Democratic presidential nominee has fretted to friends he's worried he will let Kamala Harris down, people close to him told CNN.

Adding to the pressure is the fact that the debate is likely to be the last marquee showdown between the two presidential tickets before the November 5th election. Harris has accepted CNN's offer for another presidential debate but Donald Trump has not.

So Walz has brought in some help to prepare: Pete Buttigieg, who is playing Vance in mock debate sessions. Buttigieg, however, has his limits when it comes to embodying the Republican senator from Ohio - he won't be growing a beard.

Buttigieg has a polished on-camera persona and is a frequent guest on Fox News where he spars with conservative hosts.

The due are are holding debate camp in northern Emmet County on the northern peninsula of Michigan.

CBS News will host the showdown Tuesday night at 9 p.m. ET in New York City. It is scheduled to last 90 minutes with no audience in the studio. It will be moderated by Norah O'Donnell and Margaret Brennan.

There will be no opening statements but there will be closing statements. CBS News said it reserves the right to mute the candidates' microphones, but otherwise, they will be hot. 

In his interview with Harris for the vice presidential slot, Walz warned her he is a bad debater.

'He's a strong person,' Minnesota Sen. Amy Klobuchar told CNN of her state's governor. 'He's just not a lawyer-debater type. It's not like he was dreaming of debates when he was in first grade.' 

Vance, in contrast, attended Yale and honed his debate skills at the Ivy League university.

Walz' allies worry the Republican running mate will weaken Walz's jokey dad persona and make the Democratic running mate look like moron or an out-of-touch liberal vouching for another liberal. 

Republican Rep. Tom Emmer of Minnesota, who is helping Vance prepare for the debate by playing Walz, gave a preview of their attack line on Sunday.

Walz is 'like Gavin Newsom in a flannel shirt,' Emmer told ABC's This Week.

Emmer also sat down with DailyMail.com last week to talk about debate preparations.

'I've spent the last month going through all of his debates,' he said in an exclusive interview. 'If I do my job, J.D. is going to expose him.'

'I basically have spent the last month studying all the things that Tim Walz has done,  how he tries to play himself off as something that he's not.'

'When the senator and I are talking that's exactly what I'm going to show him and he will know how to deal with that 'Minnesota Nice' fraud personality.'

Walz, a former football coach, does have a game plan: skip Vance and go straight to attacking Trump.

The Minnesota governor will use likability to hammer Vance over 'Project 2025' and for 'selling his soul to Donald Trump,' CNN reported. 

He may even borrow from Harris' playbook. When she was preparing for a vice presidential debate - before Joe Biden dropped out - she planned on asking Vance what promises he made to Trump so the former president wouldn't send an angry mob after him like Mike Pence experienced on January 6. 

After the vice presidential debate, Harris and Walz will campaign together via  bus tour through Central Pennsylvania, per the campaign.

The visit on Wednesday will be the first time that Harris and Walz have campaigned together in Central Pennsylvania. They will make multiple stops along the way to meet with voters.