Question: Who was the prime-time host of 12 Olympic Games that Michele O'Callaghan did makeup for?

Context paragraphs:
Terry Leibel: Terry Leibel is a retired Canadian journalist and former member of the Canadian Equestrian Team.  After her career as an equestrian athlete throughout the 1970s, Leibel was hired by CBC Sports as an equestrian sports analyst.  She was the first woman to host a CBC Olympic Games broadcast.  She left the CBC for TSN in 1984 where she was the first woman to host a national sports program, "SportsDesk", and worked there for two years before returning to the CBC.  She became the first woman to co-host CBC Sports Olympic coverage during the 1996 Summer Olympic Games in Atlanta, Georgia.  She also covered the 2002 and 2006 Winter Olympic Games and the 2004 Summer Olympic Games.  She earned Gemini Award nominations for her work in the Atlanta and Sydney Olympics and won a 2003 Gemini Award becoming the first female sports broadcaster to do so.  She was also the first woman to do play-by-play for the Olympics, handling cycling, equestrian and white-water events for NBC Sports during the Summer Games in Barcelona in 1992.

List of Olympic Games host cities: This is a list of host cities of the Olympic Games, both summer and winter, since the modern Olympics began in 1896.  Since then, summer games have usually but not always celebrated a four-year period known as an Olympiad.  There have been 28 Summer Olympic Games held in 23 cities, and 22 Winter Olympic Games held in 19 cities.  In addition, three summer and two winter editions of the Games were scheduled to take place but later cancelled due to war: Berlin (summer) in 1916; Tokyo/Helsinki (summer) and Sapporo/Garmisch-Partenkirchen (winter) in 1940; and London (summer) and Cortina d'Ampezzo, Italy (winter) in 1944.  The 1906 Summer Olympics were officially sanctioned and held in Athens.  However, in 1949, the International Olympic Committee (IOC), decided to unrecognize the 1906 Games.  Five cities have been chosen by the IOC to host upcoming Olympic Games: Pyeongchang for the 2018 Winter Olympics, Tokyo for the 2020 Summer Olympics, Beijing for the 2022 Winter Olympics, Paris for the 2024 Summer Olympics, and Los Angeles for the 2028 Summer Olympics.

Bob Costas: Robert Quinlan Costas (born March 22, 1952) is an American sportscaster, on the air for NBC Sports television since the early 1980s.  He was the prime-time host of 12 Olympic Games, from 1992 until 2016.  Costas currently does play-by-play for MLB Network and hosts an interview show called "Studio 42 with Bob Costas".

Youth Olympic Games: The Youth Olympic Games (YOG) is an international multi-sport event organized by the International Olympic Committee.  The games are held every four years in staggered summer and winter events consistent with the current Olympic Games format.  The first summer version was held in Singapore from 14 to 26 August 2010 while the first winter version was held in Innsbruck, Austria from 13 to 22 January 2012.  The age limitation of the athletes is 14 to 18.  The idea of such an event was introduced by Johann Rosenzopf from Austria in 1998.  On 6 July 2007, International Olympic Committee (IOC) members at the 119th IOC session in Guatemala City approved the creation of a youth version of the Olympic Games, with the intention of sharing the costs of hosting the event between the IOC and the host city, whereas the traveling costs of athletes and coaches were to be paid by the IOC.  These Games will also feature cultural exchange programs and opportunities for participants to meet Olympic athletes.

Simon Clegg: Simon Clegg CBE (b. 11 Aug 1959) is one of the UK’s most experienced sports businessmen and leaders.  He has been Chief Executive of the British Olympic Association, a Championship Football Club and a European Youth Olympic Festival.  He was Chief Operating Officer of the inaugural 2015 European Games in Baku.  He has also managed the British Biathlon Team and Team GB athletes at 12 Olympic and Olympic Winter Games.  In addition he orchestrated the national political and PR campaigns to persuade the Government and Mayor of London to bid for the 2012 Olympic Games.

Michele O'Callaghan: Michele O'Callaghan (September 14, 1963 – December 16, 2011) was a noted American makeup artist.  She was personal makeup artist to David Letterman on "The Late Show" for 23 years and made occasional appearances on his show.  O'Callaghan also did makeup for Bob Costas and Bryant Gumbel, as well as dozens of sports shows on every TV network.

Olympic emblem: Each Olympic Games has its own Olympic emblem, which is a design integrating the Olympic rings with one or more distinctive elements.  They are created and proposed by the Organising Committee of the Olympic Games (OCOG) or the National Olympic Committee (NOC) of the host country.  It is the responsibility of the International Olympic Committee (IOC) to approve Olympic emblems for the Olympic games.  The Olympic emblems are used in promotional materials, by sponsors of the Olympics, on the uniforms of every Olympic competitor.  All emblems are the property of the IOC.

List of people who have opened the Olympic Games: The Olympic Games are an international multi-sport event featuring both summer and winter sports, held every two years with Summer and Winter Olympic Games alternating.  During Olympic Games opening ceremonies, the sitting president of the International Olympic Committee (IOC) will make a speech before inviting a representative from the host country to officially declare that particular Games open.  The current Olympic Charter requires this person to be the head of state of the host country, although this has not always been the case.  This article lists the people who have had the ceremonial duty to declare each Olympic Games open.

2012 Winter Youth Olympics: The 2012 Winter Youth Olympic Games (German: "Olympische Jugend-Winterspiele 2012"), officially known as the I Winter Youth Olympic Games (YOG), were an international multi-sport event for youths that took place in Innsbruck, on 13–22 January 2012.  They were the inaugural Winter Youth Olympics, a major sports and cultural festival celebrated in the tradition of the Olympic Games.  Approximately 1100 athletes from 70 countries competed.  The decision for Innsbruck to host the Games was announced on 12 December 2008 after mail voting by 105 International Olympic Committee (IOC) members.  Innsbruck is the first city to host three winter Olympic events, having previously hosted the 1964 Winter Olympics and the 1976 Winter Olympics.

2008 Summer Olympics: The 2008 Summer Olympic Games, officially known as the Games of the XXIX Olympiad () and commonly known as Beijing 2008, was a major international multi-sport event that took place in Beijing, China, from 7 to 24 August 2008.  A total of 10,942 athletes from 204 National Olympic Committees (NOCs) competed in 28 sports and 302 events (a total of one event more than the schedule of the 2004 Games).  China became the 22nd nation to host the Olympic Games and the 18th to hold a Summer Olympic Games.  It was the third time that the Summer Olympic Games were held in East Asia and Asia, after Tokyo, Japan, in 1964 and Seoul, South Korea, in 1988.

Supporting paragraphs: Michele O'Callaghan Bob Costas
Answer: Robert Quinlan Costas