Image copyright Richard Termine / Sesame Workshop Image caption Sesame Street hopes Lily, a little girl muppet, will teach children about homelessness

US children's TV show Sesame Street is introducing a homeless muppet for the first time, to help its young viewers learn about the issue.

Lily is a seven-year-old girl whose family comes to stay with friends when they lose their apartment.

She tells fellow muppet Elmo about her situation while the pair paint a rainbow mural, saying sadly: "I'm not sure I want to paint anymore."

They are using the colour purple, the same shade that was in her old bedroom.

Lily explains that she had to leave the room behind, as "we don't have our own apartment anymore. And we've been staying in all different kinds of places".

On social media, some fans joked that the lovably grumpy bin-dwelling character Oscar the Grouch, who debuted in 1969, has "been homeless since the Vietnam War".

However, since he chooses to live in a dustbin and sings a song called "I Love Trash", this is likely to be his own choice.

Image copyright Getty Images Image caption Oscar the Grouch (left) receives visitors from his bin, and appears to live there happily

Sesame Workshop, the non-profit group behind Sesame Street, said there are more than 2.5 million homeless children across the US, nearly half of whom are under six.

"We know children experiencing homelessness are often caught up in a devastating cycle of trauma," the group said.

As well as the daily hardship of being homeless, those children may suffer due to "poverty, domestic violence, or other trauma that caused them to lose their home", said Sherrie Westin of Sesame Workshop.

"We want [homeless children] to know that they are not alone."

This is not Lily's first appearance on the famous street. In her 2011 debut, she was shown feeling hungry because her family didn't always have food available.

She won't appear in Sesame Street's TV episodes for now, but will feature online via YouTube, and in videos and storybooks on the Sesame Street in Communities website.

Sesame Street has been a childhood favourite since 1969, and runs on American public broadcaster PBS as well as cable channel HBO.

In 2017 the show won praise for introducing an autistic muppet - a little girl named Julia - to TV.