On 14 January 2014, Leitte released her fourth record, Axemusic - Ao Vivo, recorded live during O Maior Show do Mundo festival at Arena Pernambuco, in Recife. The album sold out within hours of its release, reaching platinum with over 123,000 copies sold that year. Among the special guests in the concert shooting were Wesley Safadão, Naldo Benny, Luiz Caldas, Wanessa and Armandinho.
In February 2014, it was reported Leitte had been meeting with producers Shea Taylor, Timbaland, Kuk Harrell, Rob Persaud and Rodney Jerkins. She then began recording English-language songs for her announced crossover album while still touring across South America, writing and producing over 30 songs in that period. She was featured in a version of "La Luz", the main single for Juanes' sixth album Loco de Amor (2014).
Leitte was approached by Pitbull and FIFA to represent Brazil in the 2014 FIFA World Cup official song along with Jennifer Lopez. The collaboration resulted in "We Are One (Ole Ola)", which sold over 5,6 million copies worldwide and was also featured in Pitbull's seventh album Globalization (2014). The trio performed the song onstage at the 2014 Billboard Music Awards and then during the championship's opening ceremony on 12 June 2014 in São Paulo, Brazil at the Arena Corinthians, which was preceded by Leitte's solo rendition of Ary Barroso's "Aquarela do Brasil". The performance helped Leitte gain widespread international recognition, and she spent over eight weeks on Billboard's Social 50 worldwide ranking.
In October 2014, Leitte announced that she chose not to renew her contract with Som Livre and revealed she was moving to Los Angeles to continue work on her new record. Later that month she released her first extended play, titled Sette, under her own label, 2Ts Entretenimento, vowing for more creative and commercial freedom. The lead single, "Matimba", was the result of a collaboration between Leitte and rappers Big Sean and MC Guimê. The second, "Cartório", featured singer Luan Santana and was one of the most played songs during Brazil's Carnival festivities in 2015.
On 26 December 2014, Leitte premiered the promotional single "Signs" in an emotional performance during The Voice Brasil's third series finale, marking her first venture into the English-speaking market as a solo pop artist. The song was written by Danny O’Donoghue, Andrew Frampton, Mark Shehan and Stephen Kipner and was featured on the soundtrack for television soap I Love Paraisópolis. A music video directed by Inês Vergara premiered on 31 July 2015. In April 2015, Leitte released her fourth fragrance, Secret. Another song entitled "Shiver Down My Spine", was released exclusively on Tidal on 22 October 2015. It was her first project linked to Roc Nation and also her first English composition, in collaboration with RØMANS. The song was featured in the 2015 sequel for the film S.O.S. Mulheres ao Mar and 2016 soap Haja Coração.