epa06843654 A woman stands near the Gary Holmes' work 'Michael' during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
A woman poses near US painter Kehinde Wiley's "Equestrian Portrait of King Philip II (Michael Jackson)" during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018.Neil Halll / EPA
Visitors look at an artwork by Hank Willis Thomas on display at the "Michael Jackson: On The Wall" exhibition at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
A woman poses amongst shoes suspended by balloons during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
A woman takes photographs during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
Dan Mihaltianu's work "The Last Days of Michael Jackson in Bucharest" is displayed during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
Dawn Mellor's works "Drawings of Michael Jackson" are displayed during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
A gallery assistant poses next to an artwork entitled "The King of Pop" by US artist Mark Ryden, on display during a photocall to promote the exhibition:"Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Daniel Leal-Olivas / AFP
A woman looks at an artwork by Keith Haring called "Untitled" on display at "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
A woman looks at an artwork by Donald Urquhart called "A Michael Jackson Alphabet" on display at the "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
Acrylic and silkscreen ink on linen portraits by Andy Warhol on display at the "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
A woman looks at artworks by Todd Gray on display at the "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
epa06843654 A woman stands near the Gary Holmes' work 'Michael' during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
A woman poses near US painter Kehinde Wiley's "Equestrian Portrait of King Philip II (Michael Jackson)" during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018.Neil Halll / EPA
Visitors look at an artwork by Hank Willis Thomas on display at the "Michael Jackson: On The Wall" exhibition at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
A woman poses amongst shoes suspended by balloons during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
A woman takes photographs during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
Dan Mihaltianu's work "The Last Days of Michael Jackson in Bucharest" is displayed during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
Dawn Mellor's works "Drawings of Michael Jackson" are displayed during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA
A gallery assistant poses next to an artwork entitled "The King of Pop" by US artist Mark Ryden, on display during a photocall to promote the exhibition:"Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Daniel Leal-Olivas / AFP
A woman looks at an artwork by Keith Haring called "Untitled" on display at "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
A woman looks at an artwork by Donald Urquhart called "A Michael Jackson Alphabet" on display at the "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
Acrylic and silkscreen ink on linen portraits by Andy Warhol on display at the "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
A woman looks at artworks by Todd Gray on display at the "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Kirsty Wigglesworth / AP Photo
epa06843654 A woman stands near the Gary Holmes' work 'Michael' during a press preview of the exhibition "Michael Jackson: On the Wall" at the National Portrait Gallery in London, Britain, on June 27, 2018. Neil Hall / EPA