Most of the advertising slots for Super Bowl LII — priced at $5 million for 30 seconds — have already been sold or are under negotiation for sale, with expectations that game revenue will bring at least $350 million to Comcast Corp.'s NBC television network, a top official said Monday.  NBC expects to earn additional ad revenue for pregame and postgame shows.

And within days of the Feb. 4 NFL championship game, the network also will air the 2018 Winter Olympics from PyeongChang, South Korea — sort of a live-sports home run.

It's rare for one television network to air both events — which will rank as some of the most-watched days on television — in the same month. The Winter Olympics' opening ceremony is scheduled for Feb. 9.

On a conference call Monday, Dan Lovinger, NBCUniversal's executive vice president for ad sales and marketing, said that advertisers are showing no signs of "sports exhaustion" and that NBC expects double-digit advertising gains over those of the Sochi Winter Olympics three years ago. Based on that, advertisers could drop an additional $935 million or more with the network on the 2018 Winter Games.

"We really could not be happier than where things stand right now," Lovinger said. The last time NBC aired a Super Bowl, in 2015, the network priced its 30-second advertisements at about $4.5 million for 30 seconds.

Lovinger said advertisers did not seem to be reluctant to buy Olympics spots, even with the recent confrontations between the United States and North Korea over nuclear-weapons tests. The Olympics typically seem to face potential threats or scandals that fade at event time, he said. With the last Summer Olympics in Rio de Janeiro, in 2016, there had been concerns over corruption and the Zika virus in Brazil.

This will be the first Olympic Games in which NBC will sell advertisers on what is called a "total audience delivery" — viewers, instead of just households. The new measurement will enable NBC to count viewers who watch Olympic events on cable networks or digital platforms, in addition to those watching the NBC broadcast-TV network.