Daniel James said he is “incredibly proud” to have joined Manchester United, though admitted his signing was "tinged with sadness" after his father passed away suddenly last month.
James joins United from Championship club Swansea City in an initial £15m deal, which could potentially rise to £18m in add-ons.
The 21-year-old has signed a five-year contract with the option of an additional year and becomes Ole Gunnar Solskjaer’s first signing as United manager.
The deal between United and Swansea was in motion before the end of the season, though was held up by the tragic death of James' father Kevan at the age of 60.
“This is one of the best days of my life and a challenge I am really looking forward to,” the Wales international said, in his first words as a United player.
“The Premier League is the best league in the world and Manchester United is the perfect place for me to continue to develop as a player.
“This is an incredibly proud moment for me and my family, however it is tinged with sadness that my father isn’t able to share this experience with us."
James paid a heartfelt tribute to his father on Instagram last month, describing him as his "inspiration".
"Thank you for everything you have ever done for me I couldn’t ask for anyone better, I will make you proud I promise," he wrote.
Solskjaer echoed much of what his first signing said with regards to football, describing James as an "exciting young winger with lots of skills, vision, exceptional pace and a good work ethic".
“He had a great season with Swansea City and has all the attributes needed to become a Manchester United player," Solskjaer added.
“We are delighted he has signed with our club and we are all looking forward to working with him. This is the perfect environment for Daniel to continue his development.”
