Musical comedy duo Ninja Sex Party have racked up millions of YouTube views with their raunchy, yet tongue-in-cheek, brand of humor.

Their first three albums, “NSFW,” “Strawberries and Cream,” and “Attitude City,” have exemplified this style, with vocalist Dan Avidan (a.k.a. Danny Sexbang) creating memorable pop-rock melodies and strong harmonized vocals to deliver the often hilarious and clever lyrics. All the while, Brian Wecht (a.k.a. Ninja Brian) handles the production, mainly a bare-bones ‘80s synthesizer.

While on the surface Ninja Sex Party may seem like simply the work of a couple of goofball YouTubers, the fact is that both the members have impressive backgrounds, musical and otherwise. Avidan fronted pop group the Northern Hues and later was half of a much more serious electronic duo called Skyhill.

Wecht has a PhD in theoretical physics and left a professorship at Queen Mary University in London to pursue a career as the keyboard-playing masked assassin Ninja Brian.

With their fourth release, “Under the Covers,” NSP are attempting to demonstrate a more serious side of themselves, as well as pay tribute to their musical heroes. The album contains covers of classic tracks from the ‘70s and ‘80s from various rock, R&B and pop artists of the era.

Backing the duo is the group Tupperware Remix Party (TWRP), who add a whole new level to the group’s sound and make the production feel fuller and more professional.

The album’s opening track, as well as its lead single, is a rendition of a-Ha’s hit, “Take On Me.”

This version sounds quite similar to the original, except for Avidan’s alteration of the song’s signature falsetto chorus, instead hitting the note at a much more natural pitch.

The second single is “Everybody Wants to Rule the World,” originally by Tears for Fears. The song is a natural fit for Avidan’s vocals and is aided by some tasteful lead guitar and a music video that makes one want to get together with some good friends and go on a cross-country road trip.

NSP tackle some big names on “Under the Covers,” including Michael Jackson (“Rock With You”), Pink Floyd (“Wish You Were Here”) and Avidan’s favorite band, Rush (an excellent cover of “Subdivisions”).

Other, more obscure, artists are covered as well, such as Oingo Boingo with “We Close Our Eyes” and King’s X’s “The Burning Down.” Possibly the most unusual is a previously released cover of the theme from the 1982 animated film, “The Last Unicorn.”

Throughout the album, Avidan’s vocals take center stage, delivering fantastic performances on most of the tracks, especially on “Everybody Wants to Rule the World,” “Subdivisions,” Van Halen’s “Jump” and “The Last Unicorn.” The instrumental work is most always true to the originals, with some occasional alterations here and there.

Released earlier this month, “Under the Covers” has been met with great fan reception, with pre-orders of the physical copy coming autographed. Due to the high number of pre-orders in need of Avidan’s and Wecht’s autographs, the CD’s delivery has been taking longer than expected.

Altogether, the album is a great look at the musical element of musical comedy. “Under the Covers” proves that while Ninja Sex Party can split the sides, the duo’s skills are nothing to laugh at.