Will Olympics be lacking in star power as problems in Rio rise?

In the past stars like Bar Refaeli, Rachel Bilson, Jesse Eisenberg and Mick Jagger have been snapped as spectators at the Olympics. However, with Zika concerns and recent reports about unclean water scaring away some athletes and commentators, celebrities have not been as vocal this year about attending the 2016 Summer Olympics.

NBC Olympics host, Bob Costas, spoke to reporters via satellite at the Television Critics Association Summer Press Tour about the dangers Rio is facing. Costas said the Mayor of Rio de Janeiro, Eduardo Paes, is very aware of the issues Brazil is facing.

“He is straightforward in acknowledging that these problems exist. They are real… Rio probably has the largest array of problems or potential problems,” he explained.

However, some notable celebrities like Ryan Seacrest, Gisele Bundchen, Adriana Lima and Alessandra Ambrosia have been vocal about their plans to attend the Olympics regardless. The New York Post reported Bundchen is set to be involved in the opening ceremony.

Lima and Ambrosio also couldn't contain their excitement about participating as NBC’s food and culture correspondents. The girls spoke with People magazine about their support for Brazil.

"Brazilians are very passionate about sports, sports run in our blood!" Lima said. "We're just so honored to have this huge event in our country."

“American Idol” host Seacrest seems to be enjoying his time in Rio, despite the silence from other Hollywood celebs.

NBC “Today” co-host, Savannah Guthrie, who is pregnant with her second child, announced she would be skipping the games due to the Zika virus concerns. Guthrie along with various athletes opted out of the Olympics this year.

Meanwhile, U.S. tennis superstar Serena Williams told Glamour magazine she was not taking the Zika virus “lightly” and that she would only travel to places that are “protected.”

However, Dr. Marc Siegel, of the Fox News Medical A-Team, told FOX411 despite various concerns, celebrities should be showing their support in Rio.

“Support from Rio would send a much more powerful message and help fight the irrational fear of the Zika virus which is growing much faster than the actual risk is,” he said. “If you are a celebrity - Unless you are pregnant, about to become pregnant, or have a partner who is, there is absolutely no reason not to go.”

Katy Perry is showing her support for Rio in her most recent single, “Rise.” The song was chosen to serve as an anthem before and during the games. Perry did not return FOX411’s request as to whether or not she was attending the games.