Pharrell Williams was overcome with emotion as he accepted an award for musical innovation at the inaugural iHeartRadio awards in the US.
The star, whose single Happy has become an international sensation, was lost for words for over a minute as Gwen Stefani presented him with the trophy.
“I never dreamt in a million, million, million years… that I would be standing here,” he eventually said.
Rihanna also took home four prizes, including artist and song of the year.
The star, who got stuck in traffic en route to the show, also won an award for having the most loyal fans.
She dedicated the award to her followers, and thanked them for embracing her, flaws and all.
“It’s not easy, what we do. It’s very difficult at times,” she said. “I never felt comfortable being anything other than myself.”
Performers at the show included Ed Sheeran, Arcade Fire, Bastille, 30 Seconds to Mars and Shakira.
Usher also took to the stage, leading a dance routine set to a never-before-heard Michael Jackson track, Love Never Felt So Good.
Owned by media company Clear Channel, iHeartRadio is one of the dominant internet radio brands in the US
Thursday’s awards show was broadcast by over 150 iHeart radio stations across the country, and 60 million votes were cast by listeners in the run-up to the ceremony.
Williams performed a 10-minute medley of his songs at the show, including Happy, Come Get It Bae and his best selling-collaboration with Daft Punk, Get Lucky.
The 41-year-old, who began his career producing songs for the likes of Justin Timberlake, Jay Z and Kelis, said he had never expected to become an artist in his own right.
“All I did was write the songs and you guys did all the heavy lifting, all the hard work,” he told the audience at the Shrine Auditorium in Los Angeles.
During the interview, Winfrey showed the singer a montage of fans from Africa, the Philippines, Iceland and many more, all singing Happy, his Oscar-nominated, gospel-tinged, feel-good anthem.
Brushing away tears, the singer said the response to the song had been “overwhelming”.
Winfrey was among the stars praising Williams’ contributions to music at Thursday’s ceremony, alongside Lady Gaga, Usher and Shakira.
“He was the person who made it cool to just be you,” said Beyonce.
Several artists were unable to attend the three-hour show due to illness.
Miley Cyrus, who is recovering from an allergic reaction to medicine she was given for a sinus infection, sent her father Billy Ray to accept the best lyrics award for her single Wrecking Ball.
“As a dad, I can’t begin to tell you how much your thoughts, your love, your support for my family and Miley mean to all of us,” the Achy Breaky Heart singer said.
Royals singer Lorde was also unwell, and thanked fans in a video for her best new artist trophy.
The full list of winners was:
Artist of the year – Rihanna
Song of the year – Rihanna feat. Mikky Ekko, Stay
R&B song of the year – Rihanna, Pour It Up
Country song of the year – Blake Shelton, Boys ‘Round Here
Dance song of the year – Avicii, Wake Me Up
Alternative song of the year – Imagine Dragons, Demons
Innovator award – Pharrell Williams
Best collaboration – Pitbull feat. Ke$ha, Timber
Best lyrics – Miley Cyrus, Wrecking Ball
Best new artist – Lorde
Best fanbase – Rihanna
Instagram award – Austin Mahone
Young influence – Ariana Grande