Singer Leona Lewis today cancelled a promotional tour to Germany after she was punched in the face by a fan.

Shocked: Leona Lewis was punched in the face

The X-Factor star was set to fly out this morning for a series of interviews to promote her new track “Happy”.

But a spokesman today she was too upset to leave her home after being attacked as she signed copies of her single.

The 24-year-old star was “devastated” after the assault by a 6ft 5in tall man who had queued with hundreds for fans for yesterday's event at Waterstone's in Piccadilly.

Caught: the man who punched Leona

The attacker was today being question by police on suspicion of causing actual bodily harm. Police were investigating if he had a history of mental health issues.

Not so happy: the singer had been signing copies of her new book

Witnesses say the man suddenly lashed out at the singer after she had signed his copy of her autobiography Dreams.

Miss Lewis, who won the The X Factor in 2006, reportedly screamed “oh my God” as the man caught her on the temple with a right hook as she shouted “I love you”.

Five security guards immediately wrestled the man to the ground but witnesses said he was laughing as he was dragged away.

He was described as skinny, with mousy brown long hair and wearing scruffy jeans and a jacket.

Miss Lewis, who was wearing sunglasses, was seen leaving the scene in tears clutching her face in agony. She needed treatment for a cut to her face.

Video: Leona Lewis career highlights

The singer, who now lives in Los Angeles, had returned to the UK where she is due to perform at the Hackney Empire in November.

Her spokesman, who witnessed the attack, told the Standard the singer was “incredibly shaken up” after the incident.

He said: “It was absolutely horrible. Leona had been happily signing books and chatting to her fans for 90 minutes. Hundreds of people had queued to see her since the middle of the night.

“This guy just sat down and before Leona knew what was happening he punched her. It was a proper punch straight in the face. She is absolutely devastated and incredibly shaken up. She was in pain and when police arrived, they advised her to go and see a doctor.”

Miss Lewis's boyfriend Lou Al-Chamaa reportedly tried to confront the man and had to be held back. Witnesses described the singer's mother, Maria, as “angry and shocked”.

Miss Lewis, whose first album sold six million copies worldwide, was then reportedly taken to a top Harley Street clinic and checked for concussion.

Fan Peter O'Connor, 30, from Hertfordshire, had queued for hours to see Lewis and said there were 20 people in front of him in the queue when the singer was attacked.

He said: “I heard the loud thump of the man punching Leona and then he stood up and five security guards jumped on him and dragged him away. As he was being taken away he was laughing.
“Leona looked hurt and was holding her face. The rest of us were in total shock.”

Lewis won ITV1 talent contest the X Factor in 2006 and scored a worldwide number one hit with her follow-up single Bleeding Love.

The star was due to appear on the One Show on BBC1 after the signing? last night - but was forced to pull out.

Her spokesman added: “Leona will see how she is feeling today and will decide if she's up to working. At the moment, she's too shaken up to think about any of that.”

Fans had queued from the early hours to see the singer. Lewis arrived at the bookshop at 3pm and worked her way through 200 copies of the book before she was punched at around 4.30pm.

Before the signing she spoke of her excitement at being back in the UK and how she was looking forward to performing at the Hackney Empire.

Student Jose Barbosa. 23, from west London, had already had his book signed when Lewis was assaulted.

He said: “Leona was in such high spirits. She had given most of the people hugs even though security told us we wouldn't be allowed to touch her.

“She signed the guy's book and then he suddenly hit her hard in the face. People heard a loud smack. I saw Leona leaving the shop and she was visibly shaken. Her face was red and she had been crying.

“Leona's boyfriend and mother were there. They were both upset and her mother looked incredibly angry and shocked.”

A spokeswoman for the singer added: “She's obviously in shock and some pain and a little bit bruised.

“She was due to fly to Germany today for a promotional trip, which has been cancelled, and she would have been there today and tomorrow. She is taking today as she may have to visit the doctor.

“She is expected to fly to France this weekend but that remains to be seen. She would like to thank everyone for their messages of support.”

Video: Leona Lewis career highlights