David and Matt have a decades-strong bond and created hit shows like Little Britain and Come Fly with Me.
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In the snap, the two friends both wore suits, with Matt completing his with a red tie, as David put his arm around him. In front of the pair was a beautiful chocolate cake with several candles and "Happy Birthday David" iced on.
Referencing Matt's impressive weight loss, David joked: "I am now the chubby one."
The star's fans were delighted with the sweet image, and plenty headed to the comments to wish David a happy birthday.
One fan joked: "Blimey Matt, you look great! And that chubby old man next to you too. Just kidding, you both look great."
David and Matt reunited for the special occasion
Another added: "You both look so good together," and a third penned: "You are the most generous and fun-loving person I know. You deserve a birthday full of good things and sweetness. Happy Birthday David!!"
Despite working together for years and creating popular comedy series, David and Matt fell out in 2011. In his autobiography, Little Me, Matt explained that the pair would often have heated arguments over "trivial matters".
While promoting his own autobiography, Camp, in 2012, David said of their partnership: "Well, it's over for the time being. Whether it's over forever I don't know."
Thankfully the pair have reconciled, with them making a one-off Little Britain special in 2019, and they clearly have remained friends since.
Earlier on in the day, the 50-year-old had shared a gorgeous shot of him and his mother celebrating his special day. David had his arm wrapped around her, and wrote: "50th birthday lunch with my leading lady."
David and his mum enjoyed some time together
One fan left a beautiful comment for the pair, as they wrote: "Looking trim and handsome Mr W. Needless to say, your mum always looks gorgeous."
Last week, the Britain's Got Talent judge looked thrilled as he took his mum out for a lovely dinner in what he jokingly referred to as a "date night".
David looked incredibly dapper in a black suit coat with a red shirt, and red handkerchief, while Kathleen looked elegant in a gorgeous black and white dress.
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