Their debut disc Planet Jedward - on which the identical twin brothers tackle hits by artists as diverse as Robbie Williams, the Beastie Boys and The Undertones - replaces Eminem's Recovery at the summit this week.
The album also features the pair's mash-up of Queen's 'Under Pressure' and Vanilla Ice's 'Ice Ice Baby', which topped the Irish singles chart in February, and their cover of Blink-182's 'All The Small Things', which debuts at number 21 this week.
Behind Jedward and Eminem, Florence and the Machine's Lungs holds steady at three, while Plan B's The Defamation of Strickland Banks rebounds from eleven to seven.
The second-highest new entry of the week comes from Professor Green, who lands at 18 with debut album Alive Till I'm Dead.
Planet Jedward is released in the UK on Monday.