Ant McPartlin and Declan Donnelly relive their singing days

They once had a successful music career, and their debut album Psyche reached number five in the UK chart.

And Ant McPartlin and Declan Donnelly relived their popstar days as they shared a fun video via Instagram on Thursday, as they sang Pharrell Williams’ Happy.

The Geordie duo, both 44, were seen spending time together backstage at one of their shows when Ant surprised Dec with his ‘new look’.

Like the good old days: Ant McPartlin and Declan Donnelly relived their singing days as they joked about releasing a new album together in an Instagram video shared on Thursday

Dec gasped in surprise as he saw Ant step out in a brown fedora, which he paired with a black denim jacket, a simple top and jeans.

Admitting he liked it, Ant said: ‘I am going to wear a hat again’ before he gave Dec his own fedora and joked, ‘you can get in on the action’.

Laughing at his fellow presenter, Ant said he looked like ‘a spiv’ or ‘Frank Sinatra’, as the video showed a short clip from one of their past comedy sketches.

Singing along: The pair recreated their pop star days as they sang Pharrell Williams' Happy

Singing along: The pair recreated their pop star days as they sang Pharrell Williams’ Happy

Attire: The pair were seen spending time together backstage at one of their shows when Ant surprised Dec with his 'new look'

Your turn! Admitting he liked it, Ant said: 'I am going to wear a hat again' before he gave Dec his own fedora and joked, 'you can get in on the action'

Attire: The pair were seen spending time together backstage at one of their shows when Ant surprised Dec with his ‘new look’

New look: Dec gasped in surprise as he saw Ant step out in a brown fedora, which he paired with a black denim jacket, a simple top and jeans

New look: Dec gasped in surprise as he saw Ant step out in a brown fedora, which he paired with a black denim jacket, a simple top and jeans

Ant claimed they were Sinatra and Pharell Williams, as he claimed it would be a great duet and the pair began to sing Happy in a ‘mediocre’ way.

As Ant said they had to ‘work on our harmonies’, Dec clicked his fingers repeatedly and admitted: ‘Yea, just a little.’ 

Teasing their potential return to music, the pair joked in the caption: ‘Announcing our new album… Out Of Toon.’

Ant and Dec made music under the pseudonym PJ & Duncan from 1993 and they released three albums together, including their hit single Let’s Get Ready To Rhumble, before focusing on their presenting career 

Way back when: Laughing at his fellow presenter, Ant said he looked like 'a spiv' or 'Frank Sinatra', as the video showed a short clip from one of their past comedy sketches

Way back when: Laughing at his fellow presenter, Ant said he looked like ‘a spiv’ or ‘Frank Sinatra’, as the video showed a short clip from one of their past comedy sketches

Getting into it: Ant claimed they were Sinatra and Pharell Williams, as he claimed it would be a great duet and the pair began to sing Happy in a 'mediocre' way

Needs some work: As Ant said they had to 'work on our harmonies', Dec clicked his fingers repeatedly and admitted: 'Yea, just a little'

Getting into it: Ant claimed they were Sinatra and Pharell Williams, as he claimed it would be a great duet and the pair began to sing Happy in a ‘mediocre’ way

Joking around: Teasing their potential return to music, the pair joked in the caption: 'Announcing our new album... Out Of Toon'

Joking around: Teasing their potential return to music, the pair joked in the caption: ‘Announcing our new album… Out Of Toon’

Ant and Dec were up to their usual mischievous antics in their latest Instagram video, posted on Tuesday.

In the funny skit, Dec labelled himself ‘Deccy Potter’ as he found a magic wand behind the sofa and proceeded to use it to make Ant reappear and disappear. 

The entertaining sketch started with the presenter in his dressing room, reading his Britain’s Got Talent script when he made the magical discovery.

Boys will be boys: Ant and Dec were up to their usual mischievous antics in their latest Instagram video, posted on Tuesday

Boys will be boys: Ant and Dec were up to their usual mischievous antics in their latest Instagram video, posted on Tuesday

Magical: In the funny skit, Dec labelled himself 'Deccy Potter' as he found a magic wand behind the sofa and proceeded to use it to make Ant reappear and disappear

Magical: In the funny skit, Dec labelled himself ‘Deccy Potter’ as he found a magic wand behind the sofa and proceeded to use it to make Ant reappear and disappear

With slapstick music playing in the background, Dec pointed his wand at Ant, 44, who was reading, and made him disappear.

The Saturday Night Takeaway host then ran through the studios, stopped to sanitise his hands, before pointing his wand to a set of metal gates to make Ant reappear behind bars.

Ant howled with annoyance as he banged the bars while Dec ran off giggling.    

Amusing: The entertaining sketch started with the presenter in his dressing room, reading his Britain's Got Talent script when he made the magical discovery

Amusing: The entertaining sketch started with the presenter in his dressing room, reading his Britain’s Got Talent script when he made the magical discovery

Going, going, gone: With slapstick music playing in the background, Dec pointed his wand at Ant, 44, who was reading on the sofa

Magical: Just like that his co-host vanished

Going, going, gone: With slapstick music playing in the background, Dec pointed his wand at Ant who was reading on the sofa, and made him disappear

Health and safety: The Saturday Night Takeaway host then ran through the studios and stopped to sanitise his hands

Health and safety: The Saturday Night Takeaway host then ran through the studios and stopped to sanitise his hands