Answer by taking a quote from the following article:

Enrique Martin Morales (born December 24, 1971), commonly known as Ricky Martin, is a Puerto Rican singer, actor and author. Martin began his career at age 12 with the all-boy pop group Menudo. After five years with the group, he released several Spanish-language solo albums throughout the 1990s. He also acted on stage and on TV in Mexico, where he achieved modest stardom.

After receiving commercial success throughout Asia, Europe, and Latin America, Martin prepared his first English album in 1999 in an attempt to cross over to the United States market. The self-titled album, which debuted at number one on the Billboard 200 and sold 661,000 copies in its first week of release, became the most successful album debut on the Billboard charts by a Hispanic artist. It contained material by writers and producers such as Desmond Child, Diane Warren, William Orbit, George Noriega and his longtime childhood friend Draco Rosa. The album also featured special guests: Madonna on the Spanish-English duet "Be Careful (Cuidado con mi Corazon)" and Meja on "Private Emotion". Two weeks after the album's release, Martin was featured on the cover of Time with the title "Latin Music Goes Pop!". Before the album's release, Janet Jackson collaborated with Ricky Martin for the Latin American version of "Ask for More", a promotional single and commercial released as part of an advertising campaign for soft drink company Pepsi.  The first and most prominent single was "Livin' la Vida Loca", which reached number one in many countries around the world, including the United States, United Kingdom, Canada, Ireland and New Zealand. "Livin' la Vida Loca" is Ricky Martin's biggest hit. The video for "Livin 'La Vida Loca" was directed by Wayne Isham and starring model Nina Moric. It was followed by "She's All I Ever Had" which peaked at number two on the Billboard Hot 100. Both tracks peaked at number one on the Hot Latin Songs. "Livin' la Vida Loca" is generally seen as the song that began the Latin pop explosion of 1999 and made the transition of other Latin artists (first Jennifer Lopez and Enrique Iglesias, then later Shakira) into the English-speaking market easier. Ricky Martin became one of the top-selling albums of 1999, and was certified 7x platinum in the United States, selling over 22 million copies worldwide. In October 1999, Martin embarked on a very successful year-long Livin' la Vida Loca Tour.  After this success, a new English-language album, Sound Loaded, was released in November 2000. It debuted at number four on the Billboard 200 and was certified 2x platinum by the RIAA. "She Bangs" and "Nobody Wants to Be Lonely" (duet with Christina Aguilera) peaked at number twelve and thirteen on the Billboard Hot 100, respectively. Both singles reached number one on the Hot Latin Songs. Sound Loaded has sold over 8 million copies worldwide.  In February 2001, Martin released a Spanish greatest hits album entitled La Historia, which went to number one for five weeks on the Billboard Top Latin Albums and debuted at number eighty-three on the Billboard 200. It also topped the chart in Sweden for three weeks. The album contained reworkings of two of his early songs "Fuego Contra Fuego" and "El Amor de Mi Vida". In November 2001, an English-language greatest hits album, The Best of Ricky Martin was released outside North America. It contained two new remixes of "Amor".

Who else did he feature on his songs
Meja on "Private Emotion".