Hillary Clinton’s closest campaign aides reacted nervously after former president Bill Clinton confirmed that he planned to travel on the campaign plane to Las Vegas for her first primary debate.

“Wjc confirmed,” Huma Abedin wrote in an October 11, 2015 email sent to debate prep advisers Ron Kain and Karen Dunn as well as campaign chair John Podesta.

“This is not a positive development,” Clinton’s adviser Jake Sullivan responded.

“No. It is not,” Abedin agreed.

Uh oh. Bill is coming on the plane with us to Vegas… pic.twitter.com/gNrg8PlPxI — Charlie Spiering (@charliespiering) November 3, 2016

It appears, however, that the campaign managed to keep Bill Clinton hidden, even though he traveled with his wife to the debate.

“Bill Clinton arrived in Las Vegas with his wife Monday, but he has been keeping a low profile,” CBS reported on October 13.

Podesta informed CNN that Clinton would watch the debate on TV and not be in the audience during his wife’s first presidential primary debate.

The former president later shared a picture of himself in his hotel room after the debate to show support for Hillary.