Usher has thanked fans for their support during his "hardest times" this summer (12), revealing their notes and well wishes have meant a lot to him as he battled his ex-wife for custody of their kids.

The R&B star was granted primary custody of his two sons with Tameka Foster last month (Aug12) after a bitter court battle, and he admits messages from his devotees kept him going.

He dedicated new song Without You to fans at the iTunes Festival in London on Saturday (01Sep12), and on Sunday (02Sep12), he told the city's Capital FM radio station, "I appreciate each and every one of those (messages of support), which is why I performed Without You' to my fans last night.

"It was intended to be a very intimate moment, just to say thank you for all of their support. You know, my fans are just loyal. They've been there with me through the hardest times; they've been there with me through my greater times."

Usher's fans also helped the singer as he struggled to recover from the death of his stepson Kile Glover in late July (12) - the 11 year old never regained consciousness following a jet-ski accident in Georgia.