Aretha Franklin sent flowers to Whitney Houston's mother on Tuesday to apologize for not attending the late singer's funeral.

The soul legend was devastated to have missed Saturday's service for Whitney - who died after allegedly taking a lethal overdose of prescription medication and alcohol on February 11th - due to leg spasms and sent the arrangement of white roses, lilies, tulips and other flowers to Cissy Houston to say sorry.

A source told the New York Daily News newspaper: "Aretha was devastated she missed the service, she watched it live on TV and was texting about it the whole time.

"She's just stunned and heartbroken. She sent Cissy flowers to her house, telling her how terrible she felt, how she really wanted to be there.

"Aretha wanted to attend the burial on Sunday. But she's still not 100 per cent."

Aretha, 69, was criticized for performing a gig at Radio City Music Hall the night of the funeral but witnesses who saw her on Friday insisted she clearly wasn't well and said she had to attend the concert because it had previously been cancelled in 2010.

The source said: "I saw Aretha Friday night, and you could see in her face she wasn't well. Her leg was visibly giving her problems.

"She wanted to go to the funeral. Unfortunately, something had to drop out."

"The Radio City show was already a makeup show from 2010. She would have been sued up the wazoo if she didn't show up."

When it was suggested she simply perform at the funeral and then leave for her concert, the source added: "She couldn't do that. These are all the people she came up with through the business. She's not going to leave early with Cissy right there. And can you imagine if they had to take her out in an ambulance? She wasn't going to risk that disruption."

"She and Cissy have been friends since the 1960s. They're forever friends."