Kate Hudson and Matt Bellamy reunited on Saturday (09.07.16) to celebrate their son's birthday. The 37-year-old actress was joined by her former fiance and her eldest son Ryder, 12, - who she had with ex-husband Chris Robinson - as they celebrated their son Bingham's fifth birthday with a trip to see 'Harry Potter and The Cursed Child' in London. The 38-year-old Muse frontman shared a picture of the four of them posing in front of a poster for the play and tagged the blonde beauty in the post. Alongside the photo, he wrote: "Happy Bday Bing!!! #harrypotterandthecursedchild @katehudson xxx (sic)" And the 'Bride Wars' star shared Matt's picture and added: "Bday time #Repost @mattbellamy (sic)" Kate and Matt first met in 2010 and became engaged a year later before having their son in the July of 2011. Despite splitting up in 2014, the pair remained close friends and Kate insists that the "painful" reason behind their relationship coming to an end was that they both had "different visions" of how they wanted to live their lives. In an interview not long after they ended their four-year relationship, Kate admitted: "Relationships ending are painful, and you can choose to carry that or you can choose to reframe it. If Matt and I had a great relationship, we would still be together, but we chose to move on because we had different visions of how we wanted to live out lives." However, she said they would remain amicable and do everything they can to ensure Bingham's life is as normal as possible. She said: "It's a seamless transition. Kids just want to see their parents be cool. Everybody's cool; everybody's good."