Question: What Croatian singer performed the song "My Friend" using head voice, a particular part of the vocal range, to sing the English parts of the multiligual song?

Context articles: Tenor
List of contraltos in non-classical music
List of basses in non-classical music
My Friend (Jacques Houdek song)
Georgia Brown (Brazilian singer)
Head voice
Vitas
Tereza Kesovija
Voice type
Jacques Houdek

Tenor is a type of classical male singing voice whose vocal range is between the countertenor and baritone voice types.
 The tenor's vocal range (in choral music) lies between C, the C one octave below middle C, and A, the A above middle C.
 In solo work, this range extends up to C, or "tenor high C".
 The low extreme for tenors is roughly A♭ (two A♭ s below middle C).
 At the highest extreme, some tenors can sing up to two Fs above middle C (F).
The contralto singing voice has a vocal range that lies between the F below "middle C" (F) to two Fs above middle C (F) and is the lowest type of female voice.
 In the lower and upper extremes, some contralto voices can sing from two Bs below middle C (B) to two B♭ s above middle C (B♭ ).
 Although both men and women may have voices in the contralto vocal range, the word is usually used only in the context of a female singer.
The bass singing voice has a vocal range that lies around the second E below middle C to the E above middle C (i.e., E–E).
 As with the contralto singing voice being the rarest female voice type, the bass voice is the rarest for males, and has the lowest vocal range of all voice types.
 However, the bass voice is determined not only by its vocal range, but also by its timbre, which tends to be darker than that of a baritone voice.
"My Friend" is a song performed by Croatian singer Jacques Houdek.
 The song represented Croatia in the Eurovision Song Contest 2017.
 It was released as a digital download on 2 March 2017, and is the first Croatian entry to contain lyrics in the Italian language.
 Houdek alternates between singing in Italian using his chest register and in English using his head and falsetto registers.
Georgia Brown, pseudonym of Rossana Monti (born June 29, 1980) is an Italian Brazilian singer noted for her extensive vocal range.
 She was listed in the 2005 "Guinness World Records" for hitting the highest vocal note and for possessing the greatest vocal range for a female, claimed to be exactly eight octaves from G-G using scientific pitch notation.
 However, as of 2013, Tim Storms holds the record for the widest vocal range of any human with 10 octaves.
In vocal music, the head voice, depending on vocal pedagogy, is a particular part of the vocal range, or type of vocal register, or a vocal resonance area.
Vitaliy Vladasovich Grachov (Russian: Вита́лий Владасович Грачёв , "Vitaly Vladasovich Grachyov" ), known professionally as Vitas (Russian: Ви́тас , "Vitas"; ] ), is a Ukrainian singer who sings in Russian, and is also known as the "Russian Chayanne".
 He is known for his unique head voice and possesses a five-octave vocal range.
 His eclectic musical style incorporates elements of techno, dance, classical, jazz, and folk music.
 His song "Opera 2" and the music video for "The 7th Element" have been forwarded over email and on various social networks frequently, accounting for much of his worldwide recognition.
Tereza Ana Kesovija (] ) (born 3 October 1938) is an internationally acclaimed Yugoslav and Croatian singer.
 She is one of the most recognizable figures on the Balkan music scene, and is renowned for her wide vocal range and operatic style.
 She also had a successful career in France.
 She has held many concerts around the world.
A voice type is a particular human singing voice identified as having certain qualities or characteristics of vocal range, vocal weight, tessitura, vocal timbre, and vocal transition points ("passaggio"), such as breaks and lifts within the voice.
 Other considerations are physical characteristics, speech level, scientific testing, and vocal register.
 A singer's voice type is identified by a process known as voice classification, by which the human voice is evaluated and thereby designated into a particular voice type.
 The discipline of voice classification developed within European classical music and is not generally applicable to other forms of singing.
 Voice classification is often used within opera to associate possible roles with potential voices.
 Several different voice classification systems are available to identify voice types, including the German "Fach" system and the choral music system among many others; no system is universally applied or accepted.
Jacques Houdek (born 14 April 1981) is a Croatian singer and songwriter who represented Croatia in the Eurovision Song Contest 2017 with the song "My Friend".
 Houdek began his professional solo career in 2000 and has since published many recordings and albums out which 13 have been certified silver (5 times), gold, platinum and diamond (once).
 Houdek is one of the mentors in the Croatian version of the TV talent show "The Voice".
 During show's first season, he mentored winner Nina Kraljić.
 Aside from Croatian, he has sung and recorded in English, Italian, German, Spanish, French, Slovene, Macedonian, and Maori language.