Spanish keeper David de Gea says he is leaving Manchester United this summer, saying "it's the right time to undertake a new challenge".
The 32-year-old was a free agent as his contract at the Old Trafford club had come to an end last month.
De Gea has been at United for 12 years and played in 545 games.
"I just wanted to send this farewell message to all Manchester United supporters," he wrote in a social media post.
De Gea started his career at Atletico Madrid, but joined United for £18.9ml in 2011.
He added: "I would like to express my unwavering gratitude and appreciation for the love from the last 12 years. We've achieved a lot since my dear Sir Alex Ferguson brought me to this club.
"I took incredible pride every time I pulled on this shirt, to lead the team, to represent this institution, the biggest club in the world was an honour only bestows upon a few lucky footballers.
"It's been an unforgettable and successful period since I came here. I didn't think from leaving Madrid as a young boy we would achieve what we did together.
"Now, it's the right time to undertake a new challenge, to push myself again in new surroundings.
"Manchester will always be in my heart, Manchester has shaped me and will never leave me."