Martijn Spierenburg is the keyboardist for Dutch

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

 symphonic metal

Symphonic metal

Symphonic metal is a term used to describe heavy metal music that has symphonic elements; that is, elements that are either borrowed from classical music or, as with progressive rock music, create a style reminiscent of it, e.g...

 band Within Temptation

Within Temptation

Within Temptation is a Dutch symphonic gothic metal/rock band founded in 1996 by vocalist Sharon den Adel and guitarist Robert Westerholt. Their music is described as symphonic metal, although their earlier material, such as Enter, was gothic metal. In an interview, Den Adel said they fell into a...

.

Spierenburg joined Within Temptation after Martijn Westerholt

Martijn Westerholt

David Martijn Westerholt is the founder along with Charlotte Wessels, the keyboardist and the main songwriter of the Dutch symphonic metal band Delain...

, Robert Westerholt

Robert Westerholt

Robert Westerholt is a Dutch musician, known as the guitarist, backing vocalist and co-founder of the symphonic metal band Within Temptation. He also writes music for the band, along with the band's vocalist, and his partner, Sharon den Adel...

's brother was diagnosed with infectious mononucleosis

Infectious mononucleosis

Infectious mononucleosis is an infectious, widespread viral...

 shortly after the release of Within Temptation's second full-length studio album, Mother Earth

Mother Earth (album)

Mother Earth is the second studio album by Dutch symphonic metal/rock band Within Temptation. Originally released on December 4, 2000 in the Netherlands, and August 21, 2001 in other parts of Europe, it quickly became a success in the band's heartland, reaching platinum status in the Netherlands...

. Robert and Spierenburg had played together in The Circle, Robert's first band.
Spierenburg states that his most embarrassing gig was his first show with Within Temptation. Because of stage fright he forgot how to play half the music.
Spierenburg's favourite music varies a lot but he likes listening to Sting and Rammstein in his car, amongst others and his favourite movie is The Matrix

The Matrix

The Matrix is a 1999 science fiction-action film written and directed by Larry and Andy Wachowski, starring Keanu Reeves, Laurence Fishburne, Carrie-Anne Moss, Joe Pantoliano, and Hugo Weaving...

.

Spierenburg is responsible for co-writing the music for various Within Temptation

Within Temptation

Within Temptation is a Dutch symphonic gothic metal/rock band founded in 1996 by vocalist Sharon den Adel and guitarist Robert Westerholt. Their music is described as symphonic metal, although their earlier material, such as Enter, was gothic metal. In an interview, Den Adel said they fell into a...

, including five songs off of The Heart of Everything

The Heart of Everything

The Heart of Everything is the fourth studio album by Dutch symphonic metal/rock band Within Temptation, released by GUN Records on March 12, 2007 in Europe...

, "Our Solemn Hour", "Hand of Sorrow", "The Cross", "The Truth Beneath the Rose" and "Forgiven

Forgiven (Within Temptation song)

"Forgiven" is the fourth single from the Dutch symphonic metal/rock band Within Temptation's fourth album The Heart of Everything. It was released to promote their upcoming DVD, Black Symphony as well as being a single off the album...

".
He uses ROLAND keyboards.

Spierenburg is also responsible for the orchestral arrangements used by the band, and oversees the orchestra when the band are recording albums.