Meredith Vieira to fill in for Bob Costas in prime time Olympic coverage

Meredith Vieira will become the first woman to host Olympics primetime coverage on her own when she fills on Friday night for the ailing Bob Costas, who is battling a continuing eye infection.

With Bob Costas still sidelined by an eye infection, Meredith Vieira will make history on Friday by becoming the first woman to ever anchor NBC's prime time Olympic coverage solo.

Vieira is coming on in place of Matt Lauer, who has filled in for the last three days as Costas continues to deal with the effects of an infection that began in his left eye and spread to his right eye earlier this week. Costas called Lauer in from the "bullpen" on Tuesday, ending a streak of 157 consecutive appearances as NBC's Olympics anchor in prime time. It was the first time since 1988 that Costas did not host NBC's coverage. 

"It's an honor to fill in for him,'' Vieira said on TODAY Friday. "You think about the Olympics, and you think the athletes and then Bob Costas." 

"Bob’s eye issue has improved but he’s not quite ready to do the show," NBC Olympics Executive Producer Jim Bell told from Sochi on Thursday. "If your eyes are sensitive to bright lights, a TV studio is not the place to be."

Vieira is hoping to avoid any eyesight issues of her own. 

"It's so funny, I woke up this morning and I was feeling fine, and now my eyes are killing me,'' she said on TODAY. "I watched you guys (Matt and Al) attempt the luge. I think I'm going blind. And I'm really worried because I have to go prime time tonight." 

Vieira co-hosted the Opening Ceremony with Lauer last week, and has been in Sochi doing segments for TODAY on U.S. athletes to watch in the Games. She and Lauer were co-anchors on TODAY from 2006-2011. Before Costas, former TODAY anchor Bryant Gumbel served as primetime host of NBC's Olympic coverage and was preceded by Curt Gowdy and Bill Henry, making Vieira the first woman to do the job. Hannah Storm, Mary Carillo, Gayle Gardner and Jane Pauley have previously hosted NBC's daytime and late-night Olympic coverage. 

Meanwhile, Lauer, who has been doing double duty, could use the break.

"I'm dragging a little today, I didn't sleep at all since yesterday morning," he told on Friday. "Meredith's fantastic, she'll be great, she really will, and I know she's going to have a blast. It's fun!"

As for his plans during the prime time broadcast? "Sleep, sleep, sleep, that's my night tonight," Lauer said.

TODAY's Steve Veres contributed to this report.