Miley Cyrus has broken down during an appearance on The Ellen DeGeneres Show after an emotional pledge to the victims of tropical storm Harvey.

The 24-year-old pop singer donated $500,000 to relief efforts on behalf of her non-profit organisation, the Happy Hippie Foundation, to help the tens of thousands of Texas residents who have lost their homes.

At least 44 people have been killed and 32,000 people forced into shelters in Houston as a result of the flooding since tropical storm Harvey hit last Friday.

Watch Miley’s emotional Ellen appearance below:

“Thank you … it’ll make me cry,” the Malibu singer began after host Ellen DeGeneres’s tribute to her “amazing” work.

“So, I can’t really. I can’t really talk about it.

“I don’t know why it makes me so upset. It just really makes me just really upset.”

Visibly uncomfortable, Miley told viewers she wanted to help in any way she could, and that she “couldn’t fake” this genuine emotion.

“So I really hope people know … my Grandma’s sitting here and my Mom’s here, and I go home to my seven dogs and if I didn’t have that anymore, it’d just be really hard,” she said.

“So I’m really happy to help any way that I can and I hope people understand they can put themselves in those people’s shoes and just know what it feels like to have everything taken away from you.”

Miley is just one of several celebrities to pledge significant funds to affected residents, with football star J.J. Watt, of the Houston Texans, reaching nearly $US13 million ($A16.3 million) in donations as part of his YouCaring cause.

Ellen herself announced on Thursday she would donate $US1 million ($A1.27 million) to Watt’s page.

Oscar-winning actors Sandra Bullock and Leonardo DiCaprio have also each pledged to contribute $US1 million to organisations helping people recover from the floods.

Meanwhile, Houston native and superstar Beyonce launched a new initiative, BeyGOOD Foundation, to raise funds for Harvey victims.

Earlier this week, Miley was in high spirits when the whole Cyrus clan hopped in the car for Apple Music’s Carpool Karaoke.

The Cyrus family, including Billy Ray and Tish Cyrus and Miley’s siblings Noah, Brandi, Trace and Braison, jammed out in wigs and bandannas to Billy Ray’s classic country hit, Achy Breaky Heart.

Watch the Cyrus Family’s Achy Breaky Heart rendition below:

The family, made up of actors and singers, also belted out Miley’s Party in the USA, Noah’s Stay Together, and Trace’s band Metro Station’s Shake It, as well as a bit of Bruno Mars’ 24K Magic.