In September 1998, she recorded Polish version songs for the movie Quest for Camelot; "On My Father's Wings" ('Niech Duch Ojca niesie mnie') and duet with Andrzej Piaseczny "If I Didn't Have You" ('Jesteś blisko mnie'). She was chosen by producer and composer of the movie, David Foster. On March 1, 1999, she released an album entitled "Autoportret" ('Self-portrait'), in which she promoted with the singles "Przychodzimy tylko raz", "Skończyło się" and "Zanim wszystko się odwróci". Also in her album included a new version of the hit song "Tyle słońca w całym mieście" from the repertoire of her mother Anna Jantar and a cover of the hit "Heartbreaker" by Dionne Warwick. On June 4, 1999, Kukulska takes part in the 36th National Festival of Polish Song in Opole, where, apart from her recital, she also conducts a debut concert with Mietek Szcześniak. On March 13, 2000, the album "Tyle Słoń" is released as a recording of the concert dedicated to the memory of Anna Jantar. The event took place on February 23 at the Jewish Theatre in Warsaw, and leading Polish artists performed on stage alongside Natalia. On April 23, 2001, she presented the album entitled "Tobie", for which she was nominated for Fryderyk in the Album of the Year - Pop category. The publishing studio promoted her singles "Niepotrzebny", "Cicho ciepło" and "Jeśli ona". A bonus track of the album was the song "Z głębi serc", which was dedicated to Pope John Paul II. The album was ranked 1st OLiS with the Gold Record status, and the accompanying promotion, she takes part in 10 outdoor concerts with over 600 thousand people. In April 2004, Kukulska makes her debut at the Roma Musical Theater in Warsaw, where she plays the role of Kim, the main character of the musical Miss Saigon, which was directed by Wojciech Kępczyński. On May 12, 2005, the two-disc compilation "Po tamtej stron" was released . The first CD contains 20 songs performed by Anna Jantar, while the second one Natalia performs four songs of her mother and the song "Po tamtej stron" was specially composed for this occasion. In November 2007, she released another studio album entitled "Sexi Flexi", which was produced by the Plan B duo - Bartek Królik and Marek Piotrowski . The album received 5 nominations for the Fryderyk award and achieved the status of a Gold Record. It was promoted by